(Editor's Note: As the end of 2013 approaches, the Washington Examiner is shining a spotlight on its best columns of the year. Today, it's senior writer Philip Klein who wrote about the Iraq War that made the passage of President Obama's health care law possible. This column first ran on March 20 and can be found in its original form here.)

This week brought two milestones: It has been 10 years since the United States invaded Iraq, and three years since President Obama's health care legislation became law. It's fitting that the two events coincided, because it was the Iraq War that made the passage of Obamacare possible.

Ten years later, many supporters of the Iraq War spent this week either apologizing for or justifying their backing of the war. Personally, I supported the war at the time and the subsequent "surge" strategy, but in hindsight, given the absence of weapons of mass destruction in Iraq, it's hard to see how the endeavor was worth the tremendous financial cost and American deaths involved.

As if that weren't enough, one of the realities that should tip the scales for pro-war conservatives is that the Iraq War paved the way for one of the most significant expansions of the federal government in U.S. history.

In 2004, with the memory of the defeat of the Clinton health care plan still fresh enough in people's minds, the idea of a Democratic president passing universal health care legislation would have seemed like a distant liberal fantasy. In fact, in the Democratic primary, even Howard Dean's health care proposal (that mostly built on existing government programs) was tame by today's standards.

But by 2006, with sectarian violence escalating in Iraq, President Bush's approval rating had cratered and Democrats were able to take over both chambers of Congress in an election that was largely a backlash against the war. Exit polls showed that 56 percent of Americans who voted in that year's midterm elections opposed the Iraq War -- and 80 percent of that group voted for Democrats.

Suddenly, there was a change in what seemed politically possible. In 2007, as the Democratic presidential primary season got under way, emboldened liberal activists were able to convince all of the top contenders to release universal health care plans.

The 2008 economic collapse may have given the final boost to Obama's candidacy, but Americans' disillusionment with the Iraq War created the foundation for his call for change. Though there was little in the way of policy differences between Obama and his rivals, led by Hillary Clinton, one of the most significant factors that set him apart was that he had opposed the Iraq War from the beginning. This allowed him to argue to voters that what he lacked in experience he made up for in judgment -- an argument that he'd continue to make in the general election against Republican Sen. John McCain.

On top of Obama's 2008 victory, congressional Democrats were able to build on their gains from 2006, so that once all the votes were counted (and Sen. Arlen Specter defected) they had a filibuster-proof majority in the Senate. It was only the lopsided nature of the majorities that allowed a plan as ambitious as Obamacare to become law.

In its first go-round, the health care law passed the House despite 39 Democratic "no" votes. There were 34 Democratic "no" votes in final passage. In the Senate, Majority Leader Harry Reid had to cut some ugly deals (such as the "Cornhusker kickback" on Medicaid) to clear the 60-vote threshold, with all Democrats and zero Republicans voting for the legislation.

It's quite possible that a Democrat still would have won the White House in 2008, even had the Iraq War never been fought. But that Democrat would not likely have been Obama, nor anyone nearly as liberal. And were it not for the war, no Democratic president would have come into office with as much political capital -- or with such large majorities in Congress -- as Obama did.

It's hard to see how Obamacare would have become law if Bush had never invaded Iraq. This is a bitter pill to swallow for those conservatives who supported the war and bitterly fought Obamacare.