The news media was unusually aggressive in pointing out the, um, "factual shortcuts" in Republican vice presidential nominee Paul Ryan's convention speech on Wednesday. But that's because while his speech was "well-written, well-delivered, and well-received," it was also brazenly and "profoundly dishonest in ways large and small," says James Fallows at The Atlantic. Among Ryan's most prominent distortions: Knocking Obama for a GM plant closure that happened on George W. Bush's watch, slamming Obama for Medicare budget reductions that Ryan has also included in his spending plan, and working the partisan crowd into a lather by talking up a debt commission report that Ryan himself voted against. (Read a more thorough rundown of Ryan's prevarications here, and some conservative pushback here.) How is it that Ryan "convinced himself it was OK to say things he knew were probably wrong in front of tens of millions of people"? And why did he think he could get away with it? Here, six theories:

1. Truth-bending is just part of the Romney campaign

"Ryan's claims weren't even arguably true," says Ezra Klein at The Washington Post. But that isn't new in the Romney campaign, which just "isn't adhering to the minimum standards" of truth needed for substantive debate. "Even if you bend over backward to be generous to them," Team Romney's plans and policies force you "into the same conclusion: This doesn't add up, this doesn't have enough details to be evaluated, or this isn't true." This is the campaign Ryan joined — is it any wonder he has taken to lying?

2. And the benefits of lying outweigh the risks

"Romney and Ryan are obviously engaging in some simple cost-benefit analysis," says Paul Waldman at The American Prospect. And right now, the costs of "getting a 'Pants on Fire' rating from Politifact" aren't nearly as great as the rewards from certain "specific falsehoods they're telling about Obama." After George H.W. Bush tarred Walter Mondale's campaign with a damaging but made-up quote in a 1984 debate, Bush's press secretary was blunt: "You can say anything you want during a debate, and 80 million people hear it"; when newspapers point out the lies, "So what?" he said. "Maybe 200 people read it, or 2,000, or 20,000.'' Indeed, "the Romney campaign is clearly counting on" the idea that "most casual voters don't read editorials and fact-checker columns," says Steve Kornacki at Salon. That's a pretty safe assumption.

3. All politicians play fast and loose with the truth

Mostly, Ryan is getting dinged for "omitting key facts and nudging voters to connect dots that he himself doesn't, (and the facts) don't connect," says Aaron Blake at The Washington Post. Those are "pretty run-of-the-mill political tricks," especially at partisan conventions. "I couldn't remember ever hearing an acceptance speech so rich in untrue un-facts" as Ryan's, says Melinda Henneberger at The Washington Post. But then I looked back at 2008, and there was "plenty of stretch in Obama's and [Sarah] Palin's" speeches, and John McCain's drew even longer fact-check files than Ryan's. So maybe we're "just... more inclined to see what we used to call a shading of the facts as plain false."

4. Ryan thinks voters are too dumb to notice

Any candidate "who knows the truth, but makes a deliberate decision to deceive, is working from the assumption that Americans are suckers," says Steve Benen at The Maddow Blog. And "Ryan made painfully clear that he thinks we're all profound idiots who'll believe an endless string of lies, so long as they're packaged well and presented with conviction." That level of brazen shamelessness from a national candidate is frightening for our future, and it's also "insulting."

5. The truth about Ryan's policies is unpalatable

Ryan's misleading attacks on Obama were exacerbated by his failure to mention his own, more unpopular policies, says The New York Times in an editorial. "The reasons for that are clear: Details are a turn-off, at a boisterous convention or apparently in a full campaign." He and Romney aren't willing to scrap their little-loved plans for Medicare, Medicaid, and taxes, so they just won't talk about them. Instead, as Ryan demonstrated, they "invent a phony attack on President Obama's policies, which are public in full detail, and hope that voters get so confused that they throw up their hands and cast their vote on some other issue or on emotion."

6. Ryan is playing a high-stakes game of chicken

"Analysis of the fact that Ryan can lie the way he does requires the skills of a psychologist," says Michael Tomasky at The Daily Beast. But this level of mendacity is "new territory." Ryan let loose "a couple of lies so blatant that he's practically saying to the Democrats and the media: 'F**k you, come and get me. You can't touch me.'" And he was good — he probably swayed some swing voters, and to voters who haven't been paying attention "he looks like a nice young man." Team Obama has to "raise their game," because if they can't win the Ryan war, they're done."

Read more political coverage at The Week's 2012 Election Center.