Politics 2010: A Look Back at 12 Unpredictable Months

WASHINGTON, Dec. 29, 2010 -- From the unexpected Senate election in Massachusetts to the emergence of a conservative Tea Party movement that proved to be a force to be reckoned with during a contentious election season to a roller-coaster of victories, defeats for the White House, 2010 has been a head-spinning year for political news.

ABC News has compiled some of the highlights, which not only made headlines over the past year, but that are also likely to affect the shape of things to come in 2011.

Scott Brown Shocker

Some dubbed it the "Massachusetts Miracle" or the "Scott heard 'round the world." Whatever you call it, Republican Scott Brown's victory in the special election held to replace the late Sen. Edward M. Kennedy stunned the political world.

In an overwhelmingly Democratic state, the GOP state senator defeated the state's Democratic Attorney General Martha Coakley, who had been the heavy favorite to win until just weeks before the election. In the end, Brown was able to put together a coalition of Republican and independent voters to capture 52 percent of the vote compared with Coakley's 47 percent.

Not only did Brown scoop up a Senate seat held by Kennedy for nearly half a century, he also ended the Democrats' filibuster-proof super majority in the chamber, complicating the party's plans for passing health care reform, an issue that Kennedy said was "the cause of my life."

Many Democrats also worried that Brown's election would be a preview of things to come 10 months later in the November midterm elections -- a prediction that turned out to be correct.

Health Care Overhaul Passes

It took more than a year of debate and negotiation, but in March, the Obama administration's most important domestic priority -- health care overhaul -- got the green light from Congress, followed by the president's signature. Democrats celebrated the bill as an achievement on par with Social Security and Civil Rights legislation.

"This is what change looks like," President Obama declared. "We proved that we are still a people capable of doing big things."

The vote also appeared to be a big win for House Speaker Nancy Pelosi.

But during a heated debate on the House floor, Minority Leader John Boehner delivered a stem-winder of a speech lashing out at Democrats.

"Can you say it was done openly, with transparency and accountability -- without backroom deals, struck behind closed doors, hidden from the people?" the Ohio Republican asked. "Hell no, you can't!"

Boehner and other Republicans vowed to make the passage of the health bill one of their biggest rallying points heading into the midterm elections.

Tea Party Rallies

By the end of primary season this year, it was clear the Tea Party had emerged as a full-fledged political force.

Insurgent conservative candidates, with the backing of one or more loosely-affiliated Tea Party groups, scored a string of big wins in key races, taking down GOP Sen. Bob Bennett of Utah, Rep. Mike Castle of Delaware, Gov. Charlie Crist in Florida, Sue Lowden in Nevada and establishment candidate Trey Grayson in Kentucky.