1. The individual mandate, the crux of the suit against Obamacare, was their idea in the first place:

The mandate made its political début in a 1989 Heritage Foundation brief titled “Assuring Affordable Health Care for All Americans,” as a counterpoint to the single-payer system and the employer mandate, which were favored in Democratic circles. In the brief, Stuart Butler, the foundation’s health-care expert, argued, “Many states now require passengers in automobiles to wear seat-belts for their own protection. Many others require anybody driving a car to have liability insurance. But neither the federal government nor any state requires all households to protect themselves from the potentially catastrophic costs of a serious accident or illness. Under the Heritage plan, there would be such a requirement.” The mandate made its first legislative appearance in 1993, in the Health Equity and Access Reform Today Act—the Republicans’ alternative to President Clinton’s health-reform bill—which was sponsored by John Chafee, of Rhode Island, and co-sponsored by eighteen Republicans, including Bob Dole, who was then the Senate Minority Leader.

--Ezra Klein in “Unpopupular Mandate” in the June 25, 2012 New Yorker

2. Calling the mandate a 'tax,' the argument that won the day, was their idea, too:

In declaring the mandate a tax, [Chief Justice John] Roberts broke with President Obama, who had publicly insisted the law didn't constitute a tax.

Roberts declared that Congress could not force citizens to buy health insurance under the Commerce Clause—agreeing with the four conservative justices on that point—but that the Commerce Clause ultimately didn't matter, because the mandate fell under Congress's power to levy taxes.

Graetz said it wasn't a matter of Roberts', or any of the justices' ideology; it's simply that tax law has always been broadly interpreted. ...

“That's clearly constitutional. No one says that's not constitutional. That was upheld long ago. The only question is whether because they didn't call it a tax, that would mean it wasn't a tax,” he said. “Obviously Justice Roberts didn't think what the president called it had any legal effect.”

--Reid Pillifant, “How John Roberts Saved Obamacare,” Capital New York

I give Mitt Romney a month before he starts taking credit for it.

UPDATE: Rick Perlstein, author of “Before the Storm” and “Nixonland,” writes about the core conservatism of Obamacare (psst: individual responsibility and reduction of tax-eaters) in The New York Daily News.

This time, they were in rhythm.