The health care debate dominated news headlines constantly through the first three months of the year, until President Obama finally signed the overhaul legislation on March 23. As some aspects of the law began rolling out over the next nine months, others were brought to court over questions of constitutionality.

The United States' economy continued to struggle in 2010 as policymakers attempted to navigate the difficult transition from recession to recovery. A high, stubborn, stagnant unemployment rate serves as the backdrop to a year in which further stimulus measures were considered, the financial industry faced reform, and politicians prepared to compromise on the Bush tax cuts.

At the start of the year, advocates for immigration reform were full of hope. Powerful members of Congress had promised they'd bring a comprehensive immigration reform bill to the floor, and Obama signaled his commitment to back it. But then, along came Arizona.

The year in Iraq and Afghanistan was marked by grim milestones in the US occupation, fraudulent and confusing elections, sudden changes in military command, and a lot of leaked information. Here's what you may have missed.

Obama displayed high hopes in his State of the Union Address for the Senate to consider a climate change bill and invest in clean energy, but bipartisan efforts failed and a bill didn't gain traction, despite the worst environmental disaster in history—the BP oil spill. Meanwhile, the planet experienced a slew of natural disasters and the highest temperatures on record, setting off deadly wildfires in Russia and floods in Pakistan.