Political campaigns are not famous for hewing to any line of ethical rectitude. The First Amendment that honors free expression is never stronger than when the subject is political speech; candidates have always relied on the fact that just about nothing that they say will subject them to government censorship.
Thus it was said of Abraham Lincoln that he was a "filthy story-teller, despot, liar, thief, braggart, buffoon, usurper, monster, ignoramus, old scoundrel, perjurer, robber, swindler, tyrant, field-butcher [and] land-pirate" and that an opponent "has all the characteristics of a dog, except loyalty" (per Sam Houston). The electorate is accustomed to some level of hyperbole in the political rhetoric regularly served-up to it.
That said, we inhabit an internet era of relatively easy fact-checking. While contemporary debates are rather more focused and sometimes less personal, candidates do risk credibility when they lie about the issues in ways that are too-easily detected. There is also the risk of alienating a country saturated with ads underwritten without limit by partisans outside the campaigns. The candidates may be tarred with those zealous SuperPAC brushes.
So it is that the GOP may have made ironically appropriate choices of a beach town for their convention, and "we built it" as their theme. In the words of that old Caribbean spiritual: house built on a sand foundation will not stand (oh no). They have built a series of claims so untethered to any foundation in fact that even reliably right-wing Fox News opined that the major job creation effect of the Party's work would be to create legions of fact-checkers to keep pace with the campaign's whoppers.
The reliably liberal, but picky when it comes to those "facts" things, New York Times (people have been fired for making stuff up -- no word where they found their next work, but I have my suspicions) was similarly incensed; the grey lady pointed to the following untruthienesses in the Ryan speech alone:
Item: Mr. Obama's policies closed an auto plant in Mr. Ryan's hometown. In fact, the plant was closed by GM in 2008; Obama's policies did resurrect the US auto industry.
Item: Mr. Obama ignored the Simpson Bowles deficit reduction committee's recommendations. In fact, Mr. Ryan served on that committee and his own opposition to its findings doomed it in the House.
Item: Mr. Obama funneled $716B out of Medicare. In fact, Mr. Ryan's shadow budget did the same, and his voucher system would clearly foist further out-of-pocket costs onto seniors.
Item: Mr. Obama's policies are to blame for the downgrading of America's credit rating. In fact, it was the House-led GOP of Mr. Ryan that held the debt-ceiling increase "hostage" (their words), which directly led the S&P to lower the US rating on the basis of its demonstrably dysfunctional government.
Item: when he paused to carefully compliment Mr. Romney's tenure as Massachusetts Governor (sidestepping the delicate matter of ObRomneyCare), Ryan claimed it was done without raising taxes. In fact, it was done by closing loopholes, which has the very same revenue impact: collections went up. When folks complain about their taxes going up, it's not the rate, it's the payment.
And while we're on the subject of ObRomneyCare, it is not "government-controlled health care," as Mr. Ryan claimed, but fundamentally a baseline requirement that everyone acquire coverage from private sector insurers. That's something like how the government "controls auto liability insurance" by requiring everyone to have it. (This is controversial?)
Finally, the whole "we built it" theme intended to contrast their Party's direction with that of their socialist, reg-spewing, freedom-killing, pseudo-American opponent doesn't stand up to much scrutiny, either. It was a sentence fragment lifted from a paragraph to the effect that we are all in this together -- that we share resources, like education, the rule of law and infrastructure, to create and sustain conditions that promote each other's success. That point should also be non-controversial, but it's worth the reminder to anyone prone to the GOP's brand of hubris.
In order to win in November, the GOP will have to attract and hold the Great Moderate Middle. This convention's showplace content, however, was directed at the Fearfully Credulous Faithful who are already in the Party's sway. Worse for them, they have founded their campaign on sand that can be readily swept away when the debate is not with an empty chair.