VERNON, Conn. — An attorney for Kennedy cousin Michael Skakel said Thursday he was within his rights and had strategic considerations in waiting to file an appeal of Skakel's murder conviction that claims his trial attorney did a poor job.

Prosecutors urged a judge to dismiss Skakel's latest challenge of his 2002 murder conviction, saying the claim should have been raised in an earlier appeal and that many of the issues he cites were previously rejected. The 52-year-old nephew of Robert F. Kennedy's widow, Ethel Kennedy, did not attend the hearing in Rockville Superior Court and there was no immediate ruling.

Hubert Santos, Skakel's current attorney, said there was no obligation to file the claim earlier and to do so would have forced him to make inconsistent arguments. He said the defense wanted trial attorney Michael Sherman's cooperation in connection with an earlier appeal and was awaiting details to emerge of Sherman's tax troubles that would factor into the latest claim.

Sherman served about six months in prison for failing to pay more than $400,000 in income taxes. Sherman pleaded guilty to two misdemeanor counts of willful failure to pay income taxes.

Skakel's claim argues that Sherman had significant financial problems and didn't devote enough money to retain investigators and expert consultants. Santos noted that his appeal related to Sherman's performance came after Sherman pleaded guilty.

Skakel is serving 20 years to life in prison for the fatal beating of Martha Moxley in wealthy Greenwich in 1975, when they were 15-year-old neighbors. He recently lost a bid for parole after a hearing in which he reiterated his innocence.

Attorneys for Skakel argue in the appeal filed in 2010 that Sherman failed to challenge the state's star witness by finding witnesses who later rejected his claim that Skakel confessed to the crime. Skakel, who is seeking a new trial, says Sherman failed to obtain evidence from prosecutors and others pointing to other suspects and failed to object to improper closing arguments.

Sherman has said he did all he could to prevent Skakel's conviction.

Prosecutors say the claim against Sherman should have been raised in an earlier appeal, and contend Skakel is in procedural default.

"He, in the state's view, waived it at that point," said prosecutor Susann Gill. "He waived his opportunity."

Gill also argues that 80 percent of the issues cited, such as the claim about the star witness and improper closing arguments, were denied in an earlier appeal and that Skakel should not be allowed to raise the same issues in an effort to get a different ruling from another judge.

Santos says the issues in the latest appeal are related to the earlier challenge but are not identical. He said some of the rulings denying the earlier appeals lend support to the claims against Sherman, citing a Supreme Court ruling that stated Sherman failed to object to the prosecutor's closing argument.

"I don't think there is any procedural default whatsoever," Santos said.

The victim's 80-year-old mother, Dorthy Moxley, said the appeals are stressful. She did not attend the hearing.

"It just amazes me they have all this energy to keep pushing for these things when they just hit a stone wall every time," she said Wednesday. "I just think it's a big waste of time and money for the state of Connecticut to have to put up with all these appeals. And it's a waste of time and effort and money on my part."

Skakel's attorneys say the state's interest in finality does not trump Skakel's interest in showing he was wrongfully convicted.

"Michael Skakel is an innocent man serving an unjust sentence for a crime he did not commit. Therefore, Mr. Skakel's exercise of his constitutional rights is not a waste of time or money," Santos said.

Skakel already has lost two appeals before the Connecticut Supreme Court.

If the latest appeal is not thrown out, a trial is scheduled to start in April

Earlier on HuffPost:

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  • Michael Skakel

    FILE - In this Jan. 24, 2012 file photo, Michael Skakel looks up while listening to a statement from John Moxley, brother of victim Martha Moxley in court in Middletown, Conn. Skakel's first parole hearing has been scheduled for Wednesday, Oct. 24, 2012, at McDougall-Walker Correctional Institution in Suffield. Officials say Skakel is eligible to be released next spring if parole officials approve it. Skakel is serving 20 years to life for fatally beating Martha Moxley with a golf club in Greenwich when they were 15-year-old neighbors. (AP Photo/Jessica Hill, Pool, File)

  • Martha Mosely

    405754 08: A photo from the trial evidence of the Michael Skakel vs. the State of CT case, labeled 'Exhibit 5 Photograph of Martha Moxley,' shown May 22, 2002. Skakel was convicted in 2002 of the October 1975 murder of then neighbor Martha Moxley, both of whom were 15 at the time. (Pool Photo/Getty Images)

  • Evidence Photos from the Skakel Trial

    405754 10: A 1970s family photo of Martha Moxley's Greenwich, Conn. home from the trial evidence of the Michael Skakel vs. the State of CT case, shown May 22, 2002. (Pool Photo/Getty Images)

  • Michael Skakel

    Michael Skakel, left, is hushed by his attorney Hubert Santos, right, after speaking out of turn in court in Middletown, Conn., Tuesday, Jan. 24, 2012. Skakel is seeking a reduction in his sentence of 20 years to life in prison for killing his neighbor Martha Moxley. (AP Photo/Jessica Hill, Pool)

  • Michael Skakel

    Michael Skakel, right, is shown to his seat by a judicial marshal, left, in court in Middletown, Conn., Tuesday, Jan. 24, 2012. Skakel is seeking a reduction in his sentence of 20 years to life in prison for killing his neighbor Martha Moxley. (AP Photo/Jessica Hill, Pool)

  • Dorthy Moxley

    Dorthy Moxley, mother of Martha Moxley, right, looks back while her son John speaks to the media outside court after a sentence review hearing for Michael Skakel in Middletown, Conn., Tuesday, Jan. 24, 2012. Skakel is seeking a reduction in his sentence of 20 years to life in prison for killing his neighbor Martha Moxley. (AP Photo/Jessica Hill)

  • Skakel Sentenced to 20 Years To Life

    NORWALK, CT - Michael Skakel is escorted out of Norwalk Superior Court after being sentenced to 20 years to life in prison for the 1975 golf club beating murder of his 15-year-old neighbor Martha Moxley August 29, 2002 in Norwalk, Connecticut. Skakel, a Kennedy family nephew, was found guilty June 7, 2002 of the death. Skakel was also a teenager at the time of the murder. (Photo by Pool/Getty Images)

  • Skakel Gets 10 Years To Life

    NORWALK, CT - Michael Skakel is escorted out of Norwalk Superior Court after being sentenced to 20 years to life in prison for the 1975 murder of his neighbor Martha Moxley August 29, 2002 in Norwalk, Connecticut. Skakel, a Kennedy family nephew, was found guilty June 7, 2002 of the golf club beating death of 15-year-old Martha Moxley. Skakel was also a teenager at the time of the murder. (Photo by Pool/Getty Images)

  • Michael Skakel Sentencing

    NORWALK, CT - Dorthy Moxley speaks with the media as her son, John Moxley, stands next to her after the sentencing of Kennedy family nephew Michael Skakel August 29, 2002 in Norwalk, Connecticut. Skakel was sentenced to 20 years to life in prison for the 1975 golf club beating death of his 15-year-old neighbor Martha Moxley. (Photo by Spencer Platt/Getty Images)

  • Michael Skakel In Court For Sentencing

    NORWALK, CT - Michael Skakel (C) leaves Superior Court in handcuffs after the first day of his sentencing hearing August 28, 2002 in Norwalk, Connecticut. Skakel was convicted of the 1975 slaying of childhood friend Martha Moxley in June. (Photo by Beth Keiser-Pool/Getty Images)

  • Michael Skakel Convicted

    NORWALK, CT - Michael Skakel arrives at Superior Court June 7, 2002 in Norwalk, Connecticut. The jury, meeting for the fourth day, returned a guilty verdict, convicting Skakel of the 1975 murder of neighbor Martha Moxley. Skakel is the nephew of Ethel Kennedy, the widow of the late Senator Robert F. Kennedy. (Photo by Getty Images)

  • Michael Skakel Convicted

    NORWALK, CT - Michael Skakel arrives at Superior Court June 7, 2002 in Norwalk, Connecticut. The jury, meeting for the fourth day, returned a guilty verdict, convicting Skakel of the 1975 murder of neighbor Martha Moxley. Skakel is the nephew of Ethel Kennedy, the widow of the late Senator Robert F. Kennedy. (Photo by Getty Images)

  • Evidence Photos from the Skakel Trial

    405754 02: A photo from the trial evidence of the Michael Skakel vs. the State of CT case, labeled #29 of shaft and leaves, is shown May 22, 2002. Skakel was convicted of the October 1975 murder of then neighbor Martha Moxley, both of whom were 15 at the time. (Pool Photo/Getty Images)

  • Evidence Photos from the Skakel Trial

    405754 07: A photo from the trial evidence of the Michael Skakel vs. the State of CT case, labeled #69 Skakel family with Rushton Jr. (L), Michael, Ruston and Julie, is shown May 22, 2002. Skakel is on trial accused of the October 1975 murder of then neighbor Martha Moxley, both of whom were 15 at the time. (Pool Photo/Getty Images)

  • Moxley Murder Trial

    NORWALK, CT - Dorthy Moxley, the mother of murder victim Martha Moxley, gestures to members of the news media as she walks into Norwalk Superior Court during the trial of Kennedy cousin Michael Skakel June 6, 2002 in Norwalk, Connecticut. (Photo by Mario Tama/Getty Images)

  • Evidence Photos from the Skakel Trial

    405754 09: A Skakel family photo from the trial evidence of the Michael Skakel vs. the State of CT case shown, May 22, 2002. (From top) Michael's father Rushton Skakel, his brother Rushton Jr., his sister Julie, his brother Thomas (without shirt), and Michael (below Thomas, left). Others are unidentified. Michael Skakel, now 41, is on trial in Norwalk for the 1975 murder of then neighbor Martha Moxley in Greenwich, CT. (Pool Photo/Getty Images)

  • Evidence Photos from the Skakel Trial

    405754 03: A photo from the trial evidence of the Michael Skakel vs. the State of CT case, labeled #36 shaft of club, is shown May 22, 2002. Skakel beat to death his neighbor Martha Moxley with a golf club. (Pool Photo/Getty Images)

  • A long line of television and still cameras await

    STAMFORD, : A long line of television and still cameras await the arrival of Michael Skakel for his arraignment 14 March 2000 in Stamford, CT, for the murder of Mortha Moxley in 1975. Skakel, the nephew of the late US Senator Robert F. Kennedy, was been charged in the murder of his 15-year-old neighbor. (ELECTRONIC IMAGE) AFP PHOTO/Matt CAMPBELL (Photo credit should read MATT CAMPBELL/AFP/Getty Images)

  • In this 19 January 2000 file photo, Michael Skakel

    GREENWICH, : In this 19 January 2000 file photo, Michael Skakel (C), 39, a nephew of the late Sen. Robert Kennedy, enters the Greenwich Police Department in Greenwich, Connecticut. A court ruled 17 August 2000 that Skakel will be tried on charges that he beat a childhood friend to death 24 years ago. Judge Maureen Dennis ordered an investigation into whether Skakel, who was 15 at the time of the girl's death, should be tried as a juvenile or an adult. (ELECTRONIC IMAGE) AFP PHOTO/FILES/Stan HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)

  • Michael Skakel's art

    This image released by his attorney shows a 2008 painting titled, "Faith," made by Michael Skakel while incarcerated at the MacDougall-Walker Correctional Institution in Suffield, Conn. Skakel is serving 20 years to life for beating Martha Moxley to death with a golf club in 1975 in Greenwich, Conn., when they were 15. Skakel will get his first parole hearing Wednesday, Oct. 24, 2012 at the prison to determine whether he should be released. (AP Photo/Michael Skakel)

  • Michael Skakel's art

    This image released by his attorney shows a 2009 painting of a lobster made by Michael Skakel while incarcerated at the MacDougall-Walker Correctional Institution in Suffield, Conn. Skakel is serving 20 years to life for beating Martha Moxley to death with a golf club in 1975 in Greenwich, Conn., when they were 15. Skakel will get his first parole hearing Wednesday, Oct. 24, 2012 at the prison to determine whether he should be released. (AP Photo/Michael Skakel)

  • Michael Skakel's art

    This image released by his attorney shows an undated painting titled, "Going Home," made by Michael Skakel while incarcerated at the MacDougall-Walker Correctional Institution in Suffield, Conn. Skakel is serving 20 years to life for beating Martha Moxley to death with a golf club in 1975 in Greenwich, Conn., when they were 15. Skakel will get his first parole hearing Wednesday, Oct. 24, 2012 at the prison to determine whether he should be released. (AP Photo/Michael Skakel)

  • Michael Skakel's art

    This image released by his attorney shows a 2011 painting titled, "Hopi Clown," made by Michael Skakel while incarcerated at the MacDougall-Walker Correctional Institution in Suffield, Conn. Skakel is serving 20 years to life for beating Martha Moxley to death with a golf club in 1975 in Greenwich, Conn., when they were 15. Skakel will get his first parole hearing Wednesday, Oct. 24, 2012 at the prison to determine whether he should be released. (AP Photo/Michael Skakel)