Before the Supreme Court upheld the Affordable Care Act, the principal GOP lines of attack against the law were hyperbolic, but subjective: government takeover of health care, unconstitutional overreach, etc.
From the moment the Court determined the law stands as an exercise of Congress' taxing power, though, Republicans have gone empirical. They now say that if the mandate is a tax, then it's one of the greatest tax hikes in history.
In the wake of the decision, Rush Limbaugh said, "what we now have is the biggest tax increase in the history of the world."
But when you compare the projected revenue effect of the individual mandate to the actual revenue effects of other, actually large tax increases, the claim becomes laughable.
We used the Treasury Department's four-year data on the revenue effects of large tax increases signed by Ronald Reagan, George H.W. Bush and Bill Clinton; along with CBO projections of the revenue effect of the mandate adjusted for its GDP projections during the mandate's first four years.
The mandate is tiny by comparison. Not, as Scott Walker warned, a "massive tax increase on the people of Wisconsin and America."
As others have noted, even if you include the sum total of all the revenue-raising provisions in the ACA -- and there are many taxes in it -- it's still smaller than the Reagan, Bush and Clinton tax increases.