The share of Americans who lack health insurance coverage plunged again last quarter, according to Gallup, down to the lowest level since it started keeping track. An additional 1 percent of the American public — more than 3 million people — went from uninsured to insured over the past quarter. Unfortunately Gallup's data on this doesn't go very far back, but as you can see this is way lower than where it was when the company started counting.

Every time one of these quarterly reports comes out, I hear from conservatives saying to me that of course a law that mandates the purchase of insurance and then subsidizes it will succeed in getting people health insurance. And I agree! But conservatives didn't always.

A year or two ago, people up and down the food chain from incredibly popular conservative media celebrities to incredibly obscure conservative think tank wonks were making the case that Obamacare wasn't expanding coverage.

Rush Limbaugh used to argue that people would never sign up for Obamacare plans. National Review editor and Politico columnist Rich Lowry argued that new signups were just coming from people who were already insured. And to back up his claim, Lowry had an American Enterprise Institute health policy scholar.

Now in defense of conservatives, it's a mistake to attribute this all to the Affordable Care Act. A decline in the uninsured rate is, in part, a reflection of the growing strength of the economy and the accelerating pace of job creation.

On the other hand, conservatives also predicted that Obamacare would destroy the economy. In a 2011 press conference, John Boehner used the phrase "job killing" once every two minutes. Then in 2012 we had the best year of job creation since 2005. In 2013 we had an even better year of job creation. Then in 2014, we had an even better year, the best since 1999.