Democrats are taking direct aim at the perceived frontrunner for the GOP presidential nomination, going after Mitt Romney as a flip-flopper before he gives a major speech on health care.

Romney plans a Thursday address at the University of Michigan outlining his plans to “repeal and replace” President Barack Obama’s health care law should he win the White House in 2012.

Before the speech, the Democratic National Committee on Thursday morning will email supporters a message that attempts to poke Romney, the former governor of Massachusetts, in an area where he’s vulnerable.

The DNC email, obtained by Roll Call for an early look, accuses Romney of trying to “reinvent himself” over health care given that the plan he crafted in the Bay State served as a model for Obama’s program.

The email mockingly claims that it includes “missing slides” from a Romney “PowerPoint” on health care. The “slides” show quotes that paint Romney as having shifted positions on the issue many times over the years as he sought political office.

Democrats hope to portray Romney as ideologically inconsistent, exploiting another theme that haunted him during the 2008 nomination battle.

“Romney is tying himself in knots over health reform because he’s made the calculation that in a Republican primary his Massachusetts reforms will be viewed as the equivalent of heresy. But his record remains as clear as a bell,” the email states. “While many have accused Mitt Romney of being duplicitous, he could not have been more plain spoken than when he said in 2008 ‘I like mandates.’”

Now, of course, Romney has positioned himself as a fierce critic of health care mandates, and he says states should have the freedom to implement their own plans without the federal government. The mandate is a central element to state legal challenges to Obama’s law.

“The fact is, Mitt Romney signed into law landmark health care reform legislation that laid the groundwork for national health care reform,” the DNC email states.  “But in order to cozy up to the Republican base, he is reinventing himself and his health care plan once again.”