Republican and Democratic national conventions once were exciting and unpredictable. The nominees may already have been determined, but you never knew what might happen. Now they're all about production values and absence of controversy; but will at least one of the conventions that will take place during the next two weeks be a throwback to a bygone era?

The origin of the conventions-as-political-infomercials phenomenon is the 1968 Democratic National Convention in Chicago. Opposition to the Vietnam War was in full array. Lyndon Johnson had announced he would not seek a second term, Martin Luther King, Jr. and Robert Kennedy had been assassinated in April and June. The country was on razor’s edge, and the Democratic Party was in disarray.

Ten-thousand demonstrators (Yippies, Students for a Democratic Society, and the National Mobilization Committee to end the War in Vietnam), 23,000 police and National Guardsmen, and Chicago Mayor Richard J. Daley converged. Uniformed men splitting skulls and arresting Bill Ayres and his comrades outside the convention, and security guards roughing up CBS reporter Dan Rather inside, made for edge-of-your-seat television.

Unfortunately for the Democratic Party, President Johnson’s unpopular war in Vietnam and protests at the 1968 convention didn’t give American voters a warm fuzzy about four more years of Democratic leadership, even with mild-mannered Sen. Hubert Humphrey at the top of the ticket. Richard Nixon won big that year.

Ever since, Democrats and Republicans have worked hard to ensure nothing like that happened again; and as both parties have tinkered with the primaries and the nominating process, they gradually reduced the conventions to four-day political infomercials.

Could anything like the 1968 Democratic National Convention happen this year?

According to a joint intelligence bulletin issued Tuesday by the FBI and Department of Homeland Security (DHS), they have “high confidence” extremists will attempt to disrupt both the Republican National Convention in Tampa, Florida, this week and the Democratic National Convention next week in Charlotte, North Carolina.

How successful the Occupy Wall Street (OWS) movement, anarchists and other groups will be at causing a disruption we don’t know. Both political parties and local governments in and around the conventions are better prepared to squelch bad behavior inside and outside convention halls than ever before. One byproduct of 9/11 has been the improvement of physical security at every level. It’s taken on a high-tech military precision that didn’t exist in 1968.

Republicans have their vocal, anti-establishment Tea Party crowd to worry about; but they aren’t likely to throw a tissy fit at the convention. Despite media attempts to describe it as extremist, the Tea Party has done well and won seats in Congress playing by the rules. Sarah Palin is still going rogue, but she won’t get out of hand. She’ll confine her activities to captious commentary on Fox News.

Hurricane Isaac and Democrats attempting to upstage the Republican convention likely will be bigger disruptive influences than the Tea Party or the protesters. Besides delaying the opening of the convention, the weather may also wash out the demonstrations.

Democrats have more to worry about. They have to be concerned about how to credibly deal with OWS protesters outside their convention and distance themselves from them if they become violent and destructive. Democrats were all too willing to embrace and encourage the movement when they thought it reflected their anti-Republican, we’re-the-99-percent themes. Now it’s a liability they can’t pretend they didn’t have a hand in.

Democrats will do their best to present a unified image to the television cameras; but if you pay close attention you’ll see and hear signs of disunity.

President Obama’s campaign strategy was to have damaged Gov. Mitt Romney so badly that the President would arrive at his convention with a comfortable lead in the polls. After the convention he would widen that lead and go on to win reelection.

That strategy hasn’t worked. Despite tens of millions of dollars in negative ads, Gov. Romney and Rep. Paul Ryan will arrive at their convention with a narrow lead and momentum on their side; and they’ll leave it with a bump up in the polls.

President Obama, although he inherited a bad situation, only made it worse. He’s sitting on a time bomb of chronically high unemployment, expanding entitlements, a $16 trillion out-of-control national debt, and an unpopular war in Afghanistan. To divert attention from those problems, Democrats at their convention will spend most of their time attacking Republicans. Negative conventions turn off voters. Independent voters in particular won’t get a warm fuzzy about giving a Democratic president four more years from that approach.

Behind that façade are increasingly nervous Democratic office-holders, candidates, and political operatives. Outwardly, they are behind President Obama 1,000 percent; but if Mr. Obama loses the election he will take down many of them with him. While they are smiling and reciting talking points they’ll be thinking about their post-election strategies should President Obama lose.

Bill and Hillary Clinton will stand four-square behind President Obama; but they’ll be closing their eyes and imagining what it will be like at Hillary’s nominating convention in 2016.

As much as Democrats and a friendly media will attempt to cover up all this, rifts in the Democratic Party will show through. Nervousness inside the convention combined with protests and disruptions outside could prove a volatile mix.

Will we see a repeat of the 1968 Democratic National Convention? That’s highly unlikely. Nineteen-sixty-eight was a year like no other in American History.

Nevertheless, we will hear echoes of it, reminding us of what can happen to the political party in charge when the country goes off track. Two-thousand-twelve may be another year we likely will long remember.