12/30/2015 06:33 pm ET Updated Dec 30, 2016

Here's a Look at the Year in Illinois Politics 2015

January 1, 2015 marked the first time since 1999 that our state rang in a new year with a Republican governor-elect waiting to take office.

After 12 years of Democrats controlling the governor's office, the House and the Senate, the election of Republican Bruce Rauner was a watershed in Illinois government. It marked not only a return to shared power among the two parties, but also the arrival of a Republican who vowed to do away with the old rules by which Springfield operated.

Rauner's arrival at the Executive Mansion on Jan. 12 marked the beginning of what would be a fiery first year in office, bookended by his January attack on union "fair share" fees and the historic budget impasse, which will continue into 2016.

While Rauner's yearlong shakeup of Springfield was the overarching story in Illinois politics throughout 2015, it's far from the only one. This is a year that also will be remembered for the sudden fall of one Congress' brightest rising stars, shocking charges against one of Illinois' most revered former congressmen and, in the year's final weeks, revelations of a police killing that threatens Rahm Emanuel's political career and has city residents seeing regular protests.

Here's a quick look at the milestones from the first half of 2015:

JANUARY: Bruce Rauner is inaugurated as the state's first Republican governor in 12 years. He also is the first governor in several years to make the Executive Mansion in Springfield his home. But even before his inauguration, Rauner had suffered a defeat to Democrats in the General Assembly, who voted Jan. 8 to make Rauner's appointment of Leslie Munger as Illinois State Comptroller a two-year term. Rauner had planned to appoint Munger to a four-year term to replace Judy Baar Topinka, who had been re-elected the previous November, but died a month later.
FEBRUARY: After toning down his attacks on public employee unions during the general election campaign of 2014, Rauner goes head-to-head with unions with a Feb. 9 executive order prohibiting the collection of "fair share" fees from state employees who decline union membership but work under terms bargained by a union. Ultimately, the order proved unenforceable, but a pending U.S. Supreme Court case could change that.
MARCH: U.S. Rep. Aaron Schock was a rising Republican star in Congress: Young, bright and blessed with the best abs and Instagram account in Congress. But things went downhill fast after a Feb. 4 Washington Post article  detailed Schock's "Downton Abbey" office makeover. It proved to be the crack that burst the dam on talk of Schock's excessive spending. On March 17, with the U.S. Justice Department investigating his use of campaign funds, the 33-year-old Peoria Republican announced he would resign March 31.  He's now the subject of an investigation by the U.S. Attorney's Office in Springfield. Here's his final speech to the House from March 26:
APRIL: In February, Chicago Mayor Rahm Emanuel failed to win more than 50 percent of the total vote in the mayoral primary and, therefore, faced an April 7 run-off against Cook County Commissioner Jesus "Chuy" Garcia. Emanuel won a second term by a 56-44 percent margin. That finish would be considered a landslide in almost any race, but many interpreted Emanuel's failure to win a second term outright in February as a sign of his waning popularity.

Eight days after Emanuel's re-election, the Chicago City Council, on a 47-0 vote, approved a $5 million settlement with the mother and sister of Laquan McDonald, a 17-year-old who October had been shot 16 times by a Chicago police officer who claimed the teen had lunged at him with a knife the previous October. News coverage was minimal at the time, but by year's end, this cop killing case would be the biggest story in Illinois and among the biggest in the nation.

Two days later, on April 17, Emanuel's schools chief, Barbara Byrd-Bennett, took a leave of absence amid a federal investigation into a $23 million no-bid contract between Chicago Public Schools and her former employer, SUPES Academy. She would plead guilty to bribery charges in October.

Also in April, just as it appeared hopeful that Rauner and Democrats might get along well after reaching agreement to resolve budget problems from the previous year, Rauner announced cuts to several key state programs, including one that funded autism programs on World Autism Day, which also was Good Friday and Passover. The victims of the cuts and Democrats howled, dubbed the cuts the "Good Friday Massacre" and held a series of hearings about the cuts which later were restored.

MAY: A major pension reform law passed in December 2013 was hoped to be the state's salvation from a pension funding crisis that is consuming ever-greater chunks of the state budget and threatening the well-being of the five state public employee pension funds. But the Illinois Supreme Court on May 8 rejected the law outright. Its ruling said, in effect, that Illinois didn't have a pension funding problem; it had a pension under-funding problem that lawmakers had carelessly continued for many years. The Illinois Constitution's pension protection clause was written precisely to defend against this kind of behavior, the justices ruled. Illinois must figure out a way to pay what by year's end was a $111 billion pension liability, but trouble reaching a state budget among the state's top politicians would push pension talk off the table for the rest of the year.
On May 28former Illinois congressman and Speaker of the House Dennis Hastert was indicted for violating federal banking laws when he made false claims about large cash withdrawals from two Illinois banks. The cash was part of a $3.5 million deal "to compensate for and conceal his prior misconduct" against a person identified in the indictment only as Individual A. Though never officially confirmed, it was widely reported that the money was meant to cover up sexual misconduct that dated to Hastert's days as a wrestling coach and high school teacher before entering politics. He would plead guilty in October but details of the misconduct would not emerge. At year's end, it also was revealed that Hastert had suffered a stroke and undergone several back surgeries since his plea. JUNE: State law requires that a balanced budget be in place June 1 for the fiscal year that starts July 1. But Rauner and the Democrat-controlled Legislature agreed on virtually nothing, so the Democrats passed their own budget. They estimated it was $3 billion out of balance and asked Rauner to work with them to find cuts and new revenue to fix it. But Rauner said he wouldn't talk new taxes until the Democrats enacted some of the business and government reforms outlined in his Illinois Turnaround agenda. He vetoed the Democrats' budget except for one bill that funded elementary and secondary education. This was the start of the budget deadlock that continues today.
The second half of 2015 saw one of Illinois' most shocking corruption cases as Byrd-Bennett was charged with bribery. By year's end, however, that scandal was a mere blip on Emanuel's radar as the Laquan McDonald case became worldwide news.

Animosity between Rauner and the General Assembly's top Democrats came to a head at the Illinois State Fair.

DON'T MISS: A look at the rhetoric, budget roiling and other politics in the second half of 2015 is right here.