Today marks the opening day of the Democratic National Convention, and in the wake of last week’s Republican National Convention, we have to ask: What significance apart from grandstanding and showmanship do party conventions have in modern American politics?

One poll by Gallup, released Monday, Sept. 3, shows the effects of the GOP convention are close to neutral. Among adults nationwide, 22 percent of potential voters either could not decide whether they were more or less likely to vote for Mitt Romney or were unaffected by the convention.

The poll’s results show it is the moderate or unaffiliated section of American voters that are in the “kingmaker” position.

In the aftermath of the convention, 83 percent of Republicans were more likely to vote for Romney and 74 percent of Democrats were less likely to vote for him. But the split among independent voters was nearly even: 36 percent were more likely to vote for Romney; 33 percent were less likely; and another huge proportion — 30 percent — were undecided or not impressed.

Those numbers might be different if single, isolated facts were not taken out of the stories in which they exist to advance partisan causes. The prevalence of that practice is demonstrated alone by the existence of a whole industry that now surrounds fact-checking political speeches. Everyone from nationally known outlets such as the Washington Post to Slate and local sources from Wisconsin to Texas and sea to shining sea, have weighed in on the convention’s assertions.

But facts are only isolated moments of a story. What we need and really want is a story that connects them all together and puts them in perspective. So far, both parties have been woefully inadequate at telling Americans that story.

Maybe if the convention had not been such a showcase — the image of a bakery pastry case comes to mind — of the Republican’s tired and worn-out rhetoric, currently undecided voters would be less, well, undecided.

Instead of synthesizing the regional and local preferences of a national organization that encompasses many different places with different people and mindsets, the 2012 Republican National Convention repeated mindlessly the seconds-long sound bites (their insistence that “we built it” being just one example) and trumpeted national ideologies that distill every political participant down to a lowest common denominator rather than allowing individual members to flourish in their individualism.

As a result, we have on our hands a failure to tolerate political differences and get on with what is good for the country.

We can only hope that the Democrats’ national convention will be different. Alas, that hope is not an expectation. And even if it were, it takes two to tango: As long as one-half of the American political scene is dysfunctional and deranged, the other one-half will be unable to right the ship of state.