I'd say it will depend on how close it is. If Romney wins 4 or 5 states by less than 1% - a real nightmare of a possibility - my guess is there is a possibility of rioting.
Both sides could see fraud and vote stealing if the election goes against them. In fact, it is almost a guarantee unless one candidate or the other pulls away decisively in the final days. There is no organized group of conservatives wedded to violence who would start a riot, but scattered incidents of mayhem would be possible.
But for the moment, all the threats are coming from Obama supporters:
Despite the issue garnering a significant amount of media interest as well as the attention of the Secret Service, Obama supporters continued their threats to riot and assassinate Mitt Romney if Obama loses in the aftermath of last night's presidential debate.
As we reported last week, Twitter has been flooded recently with violent comments from Obama supporters. The increase in volume of the comments seemed to coincide with Romney's poll numbers edging higher against Obama.
Not only have Obama voters been making open threats that they will riot and cause mayhem, they have also been caught making direct threats to assassinate Mitt Romney, prompting the Secret Service to announce that it was "aware" of the threats and would "conduct appropriate follow up if necessary."
Despite the fact that the media reported extensively on threats made against Obama prior to the 2008 election, their silence on the threats made against Romney has been deafening. Indeed, the act of a few old guys hanging up empty chairs in reference to Clint Eastwood's RNC speech garnered substantially more coverage and concern from the press compared to hundreds if not thousands of tweets threatening violence against Mitt Romney.
Americans who simply display political signs expressing opposition to Obama's policies have been treated as potential violent threats by authorities in the past, and yet not a single Twitter user has faced retribution for making direct and sometimes graphic death threats against Romney.
Leftists routinely cry foul and attempt to demonize conservatives as violent extremists whenever online rhetoric gets heated, and yet when their own engage in even worse conduct, their behavior is absolved and the media is disinterested.
Before the Secret Service announced they were investigating the threats, Obama front group Think Progressattempted to imply that the whole story was somehow a racist contrivance dreamed up by the Drudge Report and Infowars.
I don't think the twitter bozos will be the instigators of any riots. That job will fall to well organized street gangs who would profit enormously from any rioting. It wouldn't take much to set it off.
In the end, I think it possible, but not likely, that widespread riots will break out if the president loses, although watch in the closing days to see if racialists like Jesse Jackson and Al Sharpton begin to warn of unrest if Obama is defeated. Other liberals may echo the threat, seeing it as a desperate attempt to stave off defeat.