For months, the Democrats have been hammering Mitt Romney. His inconsistencies, flip-flopping and record in business and politics have all been highlighted in what many observers saw as the Obama campaign’s preparation for a nasty general election campaign against the man they assumed would be the Republican nominee.

But with polls showing Romney losing ground and Newt Gingrich assuming a sizable lead in the Republican presidential race, one has to wonder why the Democrats are still obsessing about Mitt. Even more curious is their latest blast at the former Massachusetts governor that, as Politico reports, attacks him for even thinking about going negative about Gingrich. By doing so at a time when Romney can no longer be considered the inevitable nominee, the Democrats may be betraying their preference in an opponent.

Part of the explanation could be that the Democratic campaign machine has become so used to attacking Romney every time he breathes they haven’t even thought about easing up on him as he starts to lose ground.

It could also be that, like some Republicans and Romney supporters, they don’t believe the Gingrich surge is real, though anyone who has taken a good look at the raft of polls in the last three weeks showing the former Speaker’s steady rise in both national and state surveys must concede this is no bubble.

But it could also be that they don’t want to take any chances. The Democrats have concentrated their attacks on Romney specifically because, like many Republicans, they saw him as the most electable GOP candidate. Romney presented a genuine threat to Obama’s re-election because of his appeal to independents and the center of the spectrum. While the rest of the Republican field presented easy pickings for opposition researchers, Romney was different. That’s why the Obama campaign appeared ready to stoop to anything to besmirch him. Back in the summer, reports emerged of an Obama campaign plan to brand Romney as too “weird” to be president. Given that the squeaky-clean Romney has lived as conventional and square a life as anyone can imagine, that seemed to be a clear attempt to play into anti-Mormon prejudice.

So perhaps, the Democrats want to do their best to ensure that Romney doesn’t overcome Gingrich’s lead. Though Newt’s fans have convinced themselves that his debating skills will vanquish Obama next fall, Democratic strategists are licking their chops at the prospect of running against the man who shut down the federal government in 1995 and who has generated more goofy quotes and positions than anyone else in public life in recent memory. Looked at in that context, the Democrats’ crocodile tears about Romney getting tough with Gingrich must be seen as the ultimate in opportunism.

It’s far from clear Republicans will listen to any attack or attempt to highlight Gingrich’s record. But no matter what the Democrats say, Romney does need to try to remind GOP voters of what they’re in for if Gingrich becomes their nominee. While it is unlikely Republicans will care what the Democrats think, their recent statements about Romney amply illustrate who they prefer as an opponent.