Do conventions "matter"? I've attended five national political conventions, and while they are fun, and important for party regulars as a networking/enthusiasm tool, the faux-drama the media build up around them is unjustified. About the only thing that really matters, in terms of its ability to move votes -- because a lot of voters actually see it -- is the nominee's acceptance speech. The convention "bounce" is a real phenomenon. But according to Nate Silver it typically dissipates a few weeks after the event, and weeks before election day.
Two conventions in recent memory flirted with outright disaster. One was the 1988 Republican convention: after George H.W. Bush picked Dan Quayle, the week was dominated by questions about Quayle's qualifications and use of family connections to secure a spot in the National Guard, thus avoiding Vietnam. The other was the Republican 1992 convention, hijacked by culture warriors (remember Pat Buchanan's keynote speech? "There is a religious war going on in our country for the soul of America. It is a cultural war, as critical to the kind of nation we will one day be as was the Cold War itself. And in that struggle for the soul of America, Clinton & Clinton are on the other side, and George Bush is on our side.")
But neither of those problems made any observable difference in the election. Bush gave an excellent speech in 1988 (though "read my lips" would come back to haunt him), then won. And his political problems were so profound in 1992 that even a flawless convention wouldn't have made up for them.
By the same token, a lot of observers are complaining about the bland tone of Monday night's proceedings, its absence of attacks on John McCain. Well, one of the most entertaining and seemingly devastating opening night attacks came in 1988, when Ann Richards skewered Bush: "Poor George. He can't help it. He was born with a silver foot in his mouth."
By today's standards of punditry, the combination of the D's home run and the R's disaster in 1988 should have set the course for a spectacular Dukakis victory. History had other ideas.