If there’s one political challenge upon which Obama’s reelection chances rest, it’s this: He must convincingly remind Americans of the depth and severity of the economic armageddon he inherited upon taking office.

Likely nominee Mitt Romney will base his case for denying Obama a second term on the chronically high unemployment rate and the net number of jobs lost on Obama’s watch, which he will point to as proof that the President’s policies have hindered the recovery, rather than enabled it. Continued economic suffering may render swing voters receptive to this case.

Obama’s chances of persuading voters that his policies have mostly succeeded in putting the economy on track to recovery will rest heavily on whether he succeeds in reminding them of just how awful things were before those policies went into effect.

That’s why the new 17-minute campaign video that the Obama team is set to release will paint an extremely vivid picture of the crisis atmosphere that reigned in early 2009. The Obama campaign has just put out the trailer:

“How do we understand this president, and his time in office?” the narrator asks. “Do we look at the day’s headlines? Or do we remember what we as a country have been through?”

There, in a nutshell, is the question that will define this presidential election. If Americans cast their vote as a referendum on the conditions of the economy on Election Day 2012 — on “the day’s headlines” — Obama could be denied a second term.

But if the Obama team can persuade them to take a longer view — to relive the horrific economic carnage that reigned in the wake of the meltdown, to understand how difficult and dangerous an operation it was to pull the country out of its nose dive, and to appreciate that his policies have put us on track to better days ahead — then he is likely to be reelected.

A case can be made, of course, that the difficulty in winning this argument flows partly from Obama’s failings (the too-small stimulus decried by some economists). His chances for success in getting the public to take the long view will turn heavily on whether the recovery continues to accelerate, which is anything but assured. And even if it does, Obama’s political challenge remains a formidable one.

* GOP establishment still not seeing Romney break away: Dan Balz reports on a conundrum that has ensnared Romney: He needs leading Republicans to step foward and crown him the nominee, but they aren’t willing to do that until he proves he can win more decisively. Of course, their silence only continues to delay his victory.

Key nugget: “Many of those on the sidelines would like some signs from Romney that he is breaking away, according to one official who supports the former governor.”

The question heading into Super Tuesday was whether Romney’s performance would induce more top GOPers to declare the battle over. We now have our answer.

* GOP primary will drag on for months, not weeks: Relatedly, Karl Rove predicts that it will take “months, not weeks, to settle this,” again underscoring that Romney’s Super Tuesday showing fell short, ensuring that the GOP nomination battle will remain chaotic and damaging.

* The increasingly white and gray GOP electorate: Ronald Brownstein notes that the GOP primary has revealed an increasing reliance on older and whiter voters that could imperil GOP chances, given what broader demographic shifts mean for the general election:

This November, though, the electorate almost certainly will be considerably younger and more tilted toward minorities than it was in 2010. Against that backdrop, the dominance of the GOP primary race by older whites could signal challenges for the party in reaching that broader universe of voters. It also increases the likelihood that the 2012 election will generate a titanic collision between a Democratic coalition that revolves around minorities, younger voters and college-educated whites generally more comfortable with the demographic changes diversifying America; and an older, preponderantly white and heavily working-class Republican coalition heavily reliant on the voters most uneasy with those changes.

* Big Senate vote on Keystone XL today: Obama is reportedly pressuring Senate Democrats to hold the line against a GOP amendment that would remove him from a role in deciding cross-border permiting decisions. The key question is how many skittish Democrats will decide that blocking Keystone is so politically perilous that they need to break with the president.

* Mitt Romney’s class problem, ctd.: Another metric: His campaign’s fundraising has relied overwhelmingly on checks from high-rolling donors, and has struggled to tap the grassroots for small donations.

Footnote: With Romney spending huge sums to tear down his rivals, his difficulties raising money from the conservative base is why his campaign may have to tap the reserves of another high-rolling donor: Mitt Romney himself.

* Obama’s bundlers have done well for themselves: T.W. Farnam’s scoop reveals yet again that shoveling big money into our politics is a bipartisan sport: “More than half of Obama’s 47 biggest fundraisers, those who collected at least $500,000 for his campaign, have been given administration jobs.”

* Jobless claims tick back up: They are back up to their highest level in five weeks; Steve Benen has them in chart form.

* Obama allies hit Romney on Iran: John Kerry pens an Op ed in the Post pointing out that Romney is attacking the President for pursuing policies that Romney himself is advocating, underscoring that Obama and his allies recognize the urgency of pushing back hard on this latest effort to paint him as weak.

By the way, the claim that Romney isn’t proposing anything different isn’t just a Democratic argument: Iran experts who have worked for Republican presidents agree with it.

* And the whitey tape has finally been revealed! It’s a blockbuster discovery. Or maybe it isn’t.

What else?