By BEN FELLER, ASSOCIATED PRESS

WASHINGTON -- Locked in a stubbornly tight race, President Barack Obama and Republican Mitt Romney are demonstrating the urgency of the campaign's final stretch, with the incumbent alone set to cover 5,300 miles in the busiest single day of his re-election bid. Both men claimed a growing edge even as voters showed little give.

From Colorado to Iowa to ever-important Ohio, bigger crowds and late October scenery offered the feel of a campaign starting to finally crackle. Obama centered on a closing theme that voters simply cannot trust Romney, while the challenger warned of the bleak times that four more Obama years would bring.

At the majestic Red Rocks Amphitheatre in Colorado late Tuesday, Romney said Obama's promise of more of the same is "why he's slipping and it's why we're gaining."

He cast the race as moving his way during a rally of up to 10,000 at the amphitheater, a stunning setting cut into mountain rocks outside Denver. Blue lights and the Romney "R" logo lit the rocks rising on either side of the venue, and the crowd wore colored T-shirts that, viewed from afar, formed the Colorado state flag.

Romney wasn't staying in Colorado long. With just two weeks left and all three of their debates behind them, the candidates turned to travel – a lot of it.

Their mission remains to sway the small pool of undecided voters, but their increasing emphasis is to implore their millions of supporters to vote, particularly in the battleground states that allow early ballots to be cast.

Setting up for a frenetic finish, both campaigns sought to show they had enthusiasm and organization on their side.

"We have the ball, we have the lead," Obama campaign strategist David Axelrod insisted.

Obama was to campaign nearly around the clock Wednesday.

His day was taking him from Washington to Iowa, Colorado, California and Nevada, and then overnight to Florida. Not stopping to sleep in a hotel was meant to signal spirit and drive – although, with a comfortable suite on Air Force One, Obama was hardly crashing out in the coach section for his red-eye flight.

It was the first time Obama was spending the night on his plane for a domestic trip, but far from unprecedented for an incumbent scrambling to keep his job.

Across the miles, Obama was holding rallies from morning to night, appearing on "The Tonight Show" with Jay Leno and calling some voters from the plane. It is the first half of a two-day trip that will see him going to Florida, Virginia and Ohio on Thursday, with a stop sandwiched in for him to cast his vote in Chicago.

Romney, too, is picking up the pace.

He is campaigning Wednesday in Reno, Nev., and Cedar Rapids, Iowa, before a three-stop swing in Ohio on Thursday.

"His is a status quo candidacy," Romney said of Obama as he teamed with running mate Paul Ryan in Henderson, Nev., on Tuesday. Thousands gathered at Red Rocks to hear him, although the sound system made him sound distant.

A swell of public polling showed an up-for-grabs race.

The Obama campaign had clearly heard the complaint that Obama, after more than a year of speeches, had failed to articulate his second-term vision. Obama's team produced a 20-page booklet outlining his proposals and promised to distribute millions of copies. Obama himself held it up at two speeches.

In the closing phase, Obama is trying to capitalize on polls that show voters see the president as more trustworthy than Romney. The president has spiced his rhetoric with humor to temper his underlying charge – that Romney is lying about what he would do as president.

"We joke about Gov. Romney being all over the map, but it speaks to something important – it speaks of trust," Obama said in Dayton, Ohio. "Trust matters. You want to know that the person who's applying to be your president and commander in chief is trustworthy, that he means what he says."

With Obama holding an edge in the uncontested states, Romney must win more of the battlegrounds to reach the minimum 270 electoral votes for the presidency. Those states are Nevada, Colorado, Iowa, Wisconsin, Ohio, Virginia, North Carolina, Florida and New Hampshire.

All of them will be drawing enormous personal attention from Romney and Obama, their wives, their running mates and other surrogates through Nov. 6.

In those states, Romney and Obama have both focused on critical demographics – particularly female voters. Polls show more women backing Romney in recent weeks. But Romney could face some trouble over comments from Indiana Republican Senate candidate Richard Mourdock, who in a Tuesday night debate said that when a woman is impregnated during a rape, "it's something God intended."

Romney's campaign said late Tuesday that he "disagrees" with Mourdock but wouldn't say whether the campaign would ask him to stop airing a TV ad that Romney cut for Mourdock earlier this week.

Two months ago, embattled Missouri GOP Senate candidate Rep. Todd Akin said during a TV interview that women's bodies have ways of preventing pregnancy in cases of what he called "legitimate rape."

Since his comment, Akin has apologized repeatedly but has refused to leave the race despite calls to do so by leaders of his own party, including Romney.

From the Romney campaign, aides to Ryan were casting his speech Wednesday at Cleveland State University as a significant pitch.

He was to argue that Americans stuck in poverty cannot afford four more years like the past four. Ryan also planned to tell voters that Romney offers a better pathway for low-income Americans to improve their lives through opportunity and upward mobility, including school choice and public-private partnerships.

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Associated Press writers Philip Elliott in Denver, Kasie Hunt in Morrison, Colo., Josh Lederman in Washington and researcher Rhonda Shafner in New York contributed to this report.

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  • 2012 -- Barack Obama

    U.S. President Barack Obama waves to supporters following his victory speech on election night in Chicago, Illinois on November 6, 2012. (JEWEL SAMAD/AFP/Getty Images)

  • 2008 -- Barack Obama

    Nov. 4, 2008: U.S. president-elect Barack Obama waves at his supporters during his election night victory rally at Grant Park in Chicago. (JEWEL SAMAD/AFP/Getty Images)

  • 2004 -- George W. Bush

    In this Nov. 3, 2004 file photo, President George W. Bush and first lady Laura Bush salute and wave during an election victory rally at the Ronald Reagan Building and International Trade Center in Washington. (AP Photo/Charles Dharapak, File)

  • 2000 -- George W. Bush

    U.S. Republican presidential candidate and Texas Governor George W. Bush casts his vote in Austin, Texas on November 7, 2000. (PAUL RICHARDS/AFP/Getty Images)

  • 1996 -- Bill Clinton

    President Bill Clinton, wife Hillary and daughter Chelsea wave to supporters in front of the Old State House during an election night celebration in Little Rock, Ark. on Tuesday, Nov. 5, 1996. (AP Photo/David Longstreath)

  • 1992 -- Bill Clinton

    Bill Clinton and Al Gore celebrate in Little Rock, Arkansas after winning in a landslide election on November 3, 1992. (AP Photo)

  • 1988 -- George H. W. Bush

    President-elect George Bush and his family celebrate his victory on November 8,1988 at the Brown Convention Center in Houston. (WALT FRERCK/AFP/Getty Images) <em><strong>CORRECTION:</strong> An earlier version of this slide was titled "George W. Bush." It has been fixed.</em>

  • 1984 -- Ronald Reagan

    President Ronald Reagan gives a thumbs-up to supporters at the Century Plaza Hotel in Los Angeles as he celebrates his re-election, Nov. 6, 1984, with first lady Nancy Reagan at his side. (AP Photo/File)

  • 1980 -- Ronald Reagan

    President-elect Ronald Reagan and wife Nancy wave to well-wishers on Tuesday, Nov. 4, 1980 at Century Plaza Hotel in Los Angeles after his election victory. (AP Photo)

  • 1976 -- Jimmy Carter

    Democratic presidential candidate Jimmy Carter embraces his wife Rosalynn after receiving the final news of his victory in the national general election on November 2, 1976. (Photo by Hulton Archive/Getty Images)

  • 1972 -- Richard Nixon

    U.S. President Richard M. Nixon meets at Camp David, Maryland, on November 13, 1972 to discuss the Vietnam situation with Secretary of State Henry A. Kissinger (L) and Maj. Gen. Alexander M. Haig Jr.(R), Deputy Assistant to the President for National Security Affairs. (Photo by AFP PHOTO/NATIONAL ARCHIVE/Getty Images)

  • 1968 -- Richard Nixon

    President-elect Richard M. Nixon and his wife, Pat, were a picture of joy at the Waldorf-Astoria Hotel in New York, Nov. 6, 1968, as he thanked campaign workers. At left are David Eisenhower, Julie Nixon's fiance, Julie and her sister Tricia at center. (AP Photo)

  • 1964 -- Lyndon Johnson

    President Lyndon Johnson proves he's a pretty good cowhand as he puts his horse, Lady B, through the paces of rounding up a Hereford yearling on his LBJ Ranch near Stonewall, Texas, on November 4, 1964. (AP Photo/Bill Hudson)

  • 1960 -- John F. Kennedy

    Caroline Kennedy peeps over the shoulder of her father, Senator John F. Kennedy, as he gave her a piggy-back ride November 9, 1960 at the Kennedy residence in Hyannis Port, Mass. It was the first chance president-elect Kennedy had to relax with his daughter in weeks. (AP Photo)

  • 1956 -- Dwight D. Eisenhower

    President Dwight D. Eisenhower and Vice President Richard Nixon salute cheering workers and Republicans at GOP election headquarters in Washington, November 7, 1956, after Adlai Stevenson conceded. (AP Photo)

  • 1952 -- Dwight D. Eisenhower

    President-elect Dwight Eisenhower and first lady-elect Mamie Eisenhower wave to the cheering, singing crowd in the Grand Ballroom of the Hotel Commodore in New York City on Nov. 5, 1952 after Gov. Adlai Stevenson conceded defeat. (AP Photo/Matty Zimmerman)

  • 1948 -- Harry S. Truman

    U.S. President Harry S. Truman holds up an Election Day edition of the Chicago Daily Tribune, which, based on early results, mistakenly announced "Dewey Defeats Truman" on November 4, 1948. The president told well-wishers at St. Louis' Union Station, "That is one for the books!" (AP Photo/Byron Rollins)

  • 1944 -- Franklin D. Roosevelt

    President Franklin Roosevelt greets a young admirer as he sits outside his home in Hyde Park, N.Y., on election night, November 7, 1944. Behind him stands his daughter, Mrs. Anna Roosevelt Boettinger and the first lady, Eleanor Roosevelt. (AP Photo)

  • 1940 -- Franklin D. Roosevelt

    American President Franklin Delano Roosevelt (1882 - 1945) speaking to a crowd of 25,000 at Madison Square Garden in New York on Nov. 8, 1940, before his sweeping re-election for a third term. (Photo by Fox Photos/Getty Images)

  • 1936 -- Franklin D. Roosevelt

    The Republican Governor of Kansas and presidential candidate, Alfred Landon (1887 - 1987) greeting the American President Franklin Delano Roosevelt (1882 - 1945) (seated) prior to the presidential elections. Future United States President Harry S. Truman can been seen in the background. (Photo by Keystone/Getty Images)

  • 1932 -- Franklin D. Roosevelt

    Governor Franklin D. Roosevelt of New York at his Hyde Park, N.Y. home November 6, 1932, seen at the conclusion of the arduous months of campaigning following his presidential nomination in Chicago. (AP Photo)

  • 1928 -- Herbert Hoover

    President-elect Herbert Hoover is seated at a table with wife, Lou, and joined by other family members on Nov. 9, 1928. Standing from left: Allan Hoover; son; Margaret Hoover, with husband, Herbert Hoover, Jr.,at right. Peggy Ann Hoover, daughter of Herbert Hoover Jr., sits with her grandmother. (AP Photo)

  • 1924 -- Calvin Coolidge

    U.S. President Calvin Coolidge and first lady Grace Coolidge are shown with their dog at the White House portico in Washington, D.C., on Nov. 5, 1924. (AP Photo)

  • 1920 -- Warren Harding

    Senator Warren Harding, with wife Florence and his father George, shown on Aug. 27, 1920. (AP Photo)

  • 1916 -- Woodrow Wilson

    Surrounded by crowds, President Woodrow Wilson throws out the first ball at a baseball game in Washington in this 1916 photo. (AP Photo)

  • 1912 -- Woodrow Wilson

    Woodrow Wilson (1856 - 1924), the future American president, casts his vote while Governor of New Jersey, on Nov. 14, 1912. (Photo by Topical Press Agency/Getty Images)