Not long ago, Jay Rosen memorably dubbed Mitt Romney’s bid for the presidency a “post truth” campaign. Within 48 hours, we may find out whether a “post truth” candidate can be elected president.

If there is one constant to this campaign, it’s that Romney has startled many observers by operating from the basic premise that there is literally no set of boundaries he needs to follow when it comes to the veracity of his assertions, the transparency he provides about his fundraising and finances, and the specificity of his plans for the country. On the dishonesty front, this has grown more pronounced in recent days, with Romney’s embrace of the Jeep-to-China lie as a closing argument in Ohio and his absurd attacks on Obama for urging people to vote.

But the key to this is how elemental it has long been to his campaign. Romney’s entire bid for the presidency rests on a foundation of evasions and lies. David Corn explains:

The Republican presidential candidate built much of his campaign on basic untruths about the president. Romney blasted Obama for breaking a “promise” to keep unemployment below 8 percent. He claimed the president was “apologizing for America abroad.” He accused Obama of adding “nearly as much debt as all the previous presidents combined” and of cutting $500 million from Medicare. None of this was true. (See here, here, here, and here.)

All of these apocryphal statements have been essential parts of Romney’s fundamental case against Obama: He’s failed to revive the economy and he’s placed the nation at risk. Rather than stick to a discourse premised on actual differences (he believes in government investments and would raise taxes on the wealthy to fund them; I want to shrink government and cut taxes) — and bend the truth within acceptable boundaries to bolster the argument — Romney has repeatedly relied on elemental falsehoods.

But this goes well beyond Romney’s claims about Obama. It also concerns what he would do as president. Romney’s own campaign has proven unable to back up the promises in his 12 million jobs plan, even though it is the centerpiece of his governing agenda and his response to the most pressing problem facing the nation. And that’s only the beginning. Jonathan Cohn:

Here we are, a day left in the campaign, and Romney still hasn’t told us how he’d offset the cost of his massive tax cut — except to say he’d do it through deductions without raising taxes on the middle class, an approach that independent analysts have said is mathematically impossible. Romney still hasn’t provided details on his “five-point plan” to boost the economy, even though his central claim as a candidate is that he’d do more to improve growth. Romney still hasn’t told us which programs he’d cut in order to cap non-defense federal spending at 16 percent, even though independent analysts have suggested doing so would require draconian cuts few Americans would find acceptable. Even in the spotlight of a nationally televised debate, when confronted with these questions, Romney wouldn’t answer.

And let’s throw Romney’s “47 percent” comments into the mix. Within 48 hours, we may find out whether it’s possible to get elected president after advancing a set of policy proposals that amount to a sham; after openly refusing to share basic governing intentions until after the election; after shifting positions relentlessly on virtually every issue the campaign has touched upon, including the one (health care) that once was seen as central to his case for national office; after refusing to share the most basic info about his own massive fortune and about the mega-bundlers that are fueling his enormous campaign expenditures; and after writing off nearly half the nation as freeloaders.

* What precedent would a Romney victory set? Tom Edsall is thinking along similar lines. He notes Romney’s Jeep-to-China ad and concludes:

If Romney wins Ohio, every campaign in future elections is going to give much more serious consideration to lying and to open defiance of media rebuttals as a legitimate campaign expedient.

* Obama edges into slight national lead: With a handful of national polls now showing Obama with a slight lead — Pew has Obama up three — Nate Silver says there’s enough evidence to surmise that the national polls are now coming into alignment with Obama’s slight edge in the electoral college. This reduces the likelihood that state polls are wrong.

Silver now puts Obama’s chances of victory at over 86 percent, and Romney’s at just over 13 percent — meaning Obama may have climbed back to where he was just before the Denver debate. The RCP and Pollster averages both have Obama slightly ahead, too.

* Final NBC/WSJ poll mirrors 2004: The final NBC/WSJ national poll finds Obama ever so slightly ahead among likely voters, at 48-47. Chuck Todd tells us that this is exactly where George Bush and John Kerry stood in the last NBC/WSJ poll before Election Day 2004.

But perhaps the most important finding in the new poll is this one: 52 percent think the economy is recovering.

* Romney struggling to hold Virginia: A new NBC/WSJ poll finds that Obama is barely ahead in Virginia, 48-47, a turnaround from the 48-47 lead Romney held three weeks ago. It is the untold story of the cycle amid the obsessing over Ohio, but Romney may end up losing Virginia, which is also probably a must win. Nate Cohn sums it up:

10 of the 16 polls following the final debate show Obama leading in Virginia, compared to just 3 for Romney.

The case for a Romney victory rested on his slight national lead and edge in all the key southern swing states, meaning he might win if he found a hole in Obama’s midwestern firewall. If the polls are right, neither of those remains operative. RCP’s average of Virginia polls now has Obama ever so slightly ahead.

* Obama ahead in New Hampshire: The final WMUR poll finds Obama ahead in the Granite State, 50-46, higher than the 2 point lead Obama holds in the averages. There’s been some chatter to the effect that Romney could conceivably win without Ohio if he picks up Wisconsin, but he’d also need New Hampshire for any outside-shot scenario.

* Predicting Obama will win Nevada: Journalist Jon Ralston weighs in with his final prediction. He notes that an enormous percentage of the vote has already taken place in Nevada, negating whatever turnout advantage Romney will have tomorrow, and predicts Obama will carry the state, 50-46. Ralston was one of the few to predict a Harry Reid victory in 2010, against overwhelming odds, so take this seriously.

* How the Obama campaign view the electoral map: The Obama campaign sees him tied or ahead in virtually all the battlegrounds, with far more routes to 270. Obama can lose in Colorado, Florida, Virginia and North Carolina and even a couple more and still win.

* How the Romney campaign views the electoral map: It’s striking how heavily the case for a Romney win rests on the bet that the electorate will be older and whiter than in 2008 — Romney aides are hoping for an electorate that is plus-one or plus-two Republican.

The fact of the matter is that the polling averages track overwhelmingly with the Obama camp’s view of the race, and not at all with the Romney camp’s view of the race.

* Celebs for Elizabeth Warren: The Progressive Change Campaign Committee is out with a new Web video featuring celebrities like Ben Affleck and Sarah Silverman making the case for Warren. The RCP average of Massachusetts Senate race polls puts her ahead by 3.5 points.

* And Sandy reminds us that government is a good thing: Paul Krugman makes it simple: Federal disaster response is weaker under Republican presidents because they don’t value the federal government’s role in responding to disasters. That includes Romney, and it goes beyond just disaster response:

The fact is that if Mr. Romney had been president these past four years the federal response to disasters of all kinds would have been far weaker than it was. There would have been no auto bailout, because Mr. Romney opposed the federal financing that was crucial to the rescue. And FEMA would have remained mired in Bush-era incompetence.

What else?