President Obama, during his event just now calling on Congress to extend the Bush tax cuts on those making under $250,000:

We should all agree to extend the tax cuts for the middle class. Let’s agree to do what we agree on. Right? That’s what compromise is all about. Let’s not hold the vast majority of Americans and our entire economy hostage while we debate the merits of another tax cut for the wealthy. We can have that debate. But let’s not hold up working out the thing that we already agree on.

In many ways the fate of the tax cut for the wealthiest Americans will be decided by the outcome of the next election. My opponent will fight to keep them in place. I will fight to end them. That argument shouldn’t threaten you. It shouldn’t threaten the 98 percent of Americans who just want to know that their taxes won’t go up next year. Middle class families and small business owners — they deserve that guarantee. They deserve that certainty. It will be good for the economy, and it will be good for you.

Obama’s political imperative is to separate the battle over the Bush tax cut into two fights: One over whether to extend the middle class tax cuts; and a second one over whether to end the tax cuts on the rich. By contrast, the political imperative of Mitt Romney and Republicans is to do all they can to conflate these two battles, because if the first one were to be resolved, then they’d lose all their leverage in the second one.

What’s more, the GOP position in that second battle — whether to extend the tax cuts only on the rich — is very unpopular. Republicans can’t agree to Obama’s proposal, because it would then mean the battle over whether to extend just the tax cuts for the rich would be isolated. Obama knows this. So he’s hoping that their opposition to his proposal will clarify and separate out the two battles — and who stands for whom — in the public mind.

Meanwhile, Obama’s push will soon get a vote in the Senate. Harry Reid announced today: “Republicans have claimed they want to reduce our deficit; in the weeks ahead, they will have a chance to do so by joining Democrats to vote to extend tax cuts for all middle class American families on the first $250,000 of their income.”

By the way, people shouldn’t be surprised by today’s White House move. Senior adviser David Plouffe clearly telegraphed it with the memo he put out the other day, after the Supreme Court upheld the health law. After that ruling Republicans denounced the individual mandate as a tax, and in the memo Plouffe advised Dems to welcome the fight over taxes. He referenced a recent study finding that the loopholes that would have to be closed to pay for Mitt Romney’s proposed tax cuts — which disproportionately benefit the rich — would mean a middle class tax hike. “Republican plans will raise taxes on middle class families,” Plouffe said. He vowed that this battle would drive the argument in the “coming months.”

How much of an impact this will have on the election’s outcome is anybody’s guess, but this is shaping up as another clear sign of Obama’s aggressive use of the presidency to drive the campaign narrative on to more favorable turf.