DNC Attacks Romney Flip-Flops--But Why Now?

Being a proud cyber-card carrying, if non-contributing, member of the Democratic National Committee's email list, I just received a missive entitled "Test your knowledge: Take the Mitt quiz."  Clicking along takes one to a DNC site called "WhichMitt.com" at which readers are asked to guess whether, on a variety of subjects from abortion to the Detroit bail-out, Romney said the first statement, the second statement which contradicts the first, or all of the above.

Of course the answer in every case is "all of the above."  And there's no doubt that if nominated, and before, Mitt will have some 'splaining to do.  What's less clear is just how the Dems really think they can exploit this: "vote against Romney--he actually has agreed with us on a lot of stuff!" is probably not going to work.  Does the fact that the DNC is singling Romney out for attack long before the first GOP primary has even been cast suggest it sees him as the strongest electoral threat to President Obama?  See more about WhichMitt.com after the jump.
 

There's no question that the way Romney has, um, evolved on certain issues is remarkable. But could the DNC's true target audience for this line of attack be Republican primary voters rather than loyal Dems?  Could the DNC be trying to undermine the man they see as PBO's potentially strongest opponent?