Ronald Brownstein is one of the best writers out there at explaining the impact the country’s shifting demographics are having on our politics, so when he tells you that President Obama is having some success in reassembling his 2008 coalition, you should listen to him.

Brownstein details a new National Journal poll that finds Obama’s approval is up to 51 percent, and he’s making gains among key demographics when compared to a previous poll:

Compared with the December survey, the new poll found his approval rating rising by 11 percentage points among independents; 8 among nonwhites; 6 among all whites; 7 among both college-educated white men and women; and 9 among the so-called waitress moms — white women without a college degree. Only among noncollege-educated white men did Obama remain stuck in neutral with virtually no gain from December.

With most of these groups, Obama’s approval rating is approaching his actual share of the 2008 vote.

Since the December poll, of course, the economy has added over 200,000 private sector jobs in the last three months. The new poll also finds that the number who anticipate continued improvement over the next year is up to 60 percent — a key number, given the importance of public perceptions of the economy’s direction.

To be sure, this poll is running higher than other polls that were taken more recently, such as the ones released earlier this week; Obama is still struggling badly with blue collar whites, a key swing constituency; and the country is still sharply divided on his performance, ensuring a very close election. But things may well be slowly moving in the right direction for him. Pollster’s average Obama approval is at 47 percent.

* Obama now in full reelection mode: It’s also perhaps not a coincidence that the above shifts coincide with a stepped up effort by Obama and the White House to shift into full political mode. The Obama team has launched a full-court-press effort to get voters to take the long view of his presidency, rather than judging him through the prism of today’s state of the economy.

That’s a key goal of the full-length video documentary the campaign released last night. Getting voters to re-live the depth and severity of the crisis Obama inherited, and to accept the idea that putting the economy on a path to better days ahead is a major achievement unto itself — one that might not have happened — are crucial to his reelection chances.

* Santorum’s growing power within GOP: Nia-Malika Henderson takes stock of the astonishing level of influence that Rick Santorum has now claimed over the conservative wing of the GOP, and the problems that continues to pose for Romney’s ability to connect with crucial GOP constituencies.

In this context, it’s worth reiterating the GOP nightmare scenario: We could see Romney wining the delegate count, and the nomination, even as big chunks of the GOP feel Santorum was the rightful winner.

* GOP enthusiasm down in the dumps? Chris Cillizza and Aaron Blake ferret out a key Gallup finding: “Just 35 percent of Republicans said they would `enthusiastically’ support former Massachusetts governor Mitt Romney this November, while 42 percent said their vote would be primarily against President Obama.” John McCain did notably better in this department in a Gallup poll four years ago, even though he, like Romney, also struggled with the base and benefited from a split-conservative vote.

Key caveat: Republicans have now lived for four years under Obama’s tyrannical rule and will likely get extremely enthusiastic about their nominee, whoever he is, once the general election hits full boil.

* The GOP’s new spin on the Latino vote: Republican strategists are now trying to spin reporters into believing that the bad economy will offset the presidential contenders’ harsh anti-immigration rhetoric and allow them to make inroads among Latinos in key swing states like Colorado and Nevada. Of course, polling suggests Latinos agree with Dems on the economy, too.

* Get ready for Supreme Court arguments on health reform: Sam Baker has an interesting look at how the Obama administration is shifting its legal defense of the indidual mandate onto legal turf that experts say could be somewhat more favorable to the law. A ruling is expected in June — right when the GOP will likely be crowning its nominee.

* Dems keep hitting Romney on women’s health: The new DNC video out this morning encapsulates the whole women’s-health-issues case against Romney, recapping his “extreme” stances on abortion and birth control.

The fact that the video’s intended audience is women in Illinois — where GOP voting takes place Tuesday in a high-stakes primary —i underscores Dem hopes that these stances might weaken Romney among moderate Republicans and GOP-leaning independents.

* Marriage equality in the Dem party platform? Jonathan Bernstein notes an important point: There’s little downside in including it, since it will energize a core Dem constituency and there’s little chance the details of the party platform will sway swing voters in any case.

* Takedown of the day: Paul Krugman does a demolition job on the GOP belief, or feigned belief, in the “two miracle cures for whatever ails the economy: more tax cuts for the rich and more drilling for oil.”

Key nugget: “Employment in oil and gas extraction has risen more than 50 percent since the middle of the last decade, but that amounts to only 70,000 jobs, around one-twentieth of 1 percent of total U.S. employment. So the idea that drill, baby, drill can cure our jobs deficit is basically a joke.”

The public does seem to buy the GOP argument about Keystone, but I’m not sure anyone has polled the broader question of whether more drilling would go a long way towards fixing the economy.

* And did Obama make things worse, or are things getting better? Romney admitted last night that the economy is improving, which — presuming a world where consistency and coherence matters a little bit — would seem to undermine his continuing claims that Obama made things worse.

What else?

Update: Lead item edited for accuracy.