The Obama administration had hoped that this month's town hall meetings would smooth the way for healthcare reform. Things do not seem to be working out that way. Across the country, loud and furious protesters have turned up. They accuse the White House of wishing, among other things, to bankrupt the nation, destroy the American way of life and bring in “death panels” to mitigate the excessive healthcare demands of the elderly.

Unruly protest makes good television and is especially welcome in a slow month for news. The protesters have been dominating US newspapers and news programmes in recent days.

It is all a little misleading. Many who are sceptical about the Democrats' plans have asked intelligent questions. But this is too dull for prime-time, and before you know it, intelligent questions bog you down in complex details. Better to make the protests the story.

Rowdy demonstrations are not what the administration wanted, but in a way they have played into its hands. They have shifted the focus from the reform measures to the unreasoning anger of the least appealing opponents. In three town hall meetings the president conducted last week, he decided to attack his attackers. The idea that he ran for office “to go around pulling the plug on grandma”, as he put it, is “simply dishonest”.

“Dishonest” is putting it politely – but the point is that reasonable people will agree with him about that. And the views of reasonable people will matter much more to the fate of health reform than the protesters would lead you to think.

The gap between the right of the Republican party, which is providing the angriest critics of the reforms, and the left of the Democratic party, which thinks the proposals too timid, is unbridgeable. These groups do not merely disagree. They despise each other. Their differences are only secondarily about policy. They hold each other's values in contempt.

These snarling extremes are nonetheless somewhat alike. They have an equal and opposite penchant for conspiracy theories. Almost a third of Republicans, according to a recent poll, believe the unsupported story that Mr Obama was not born in the US (in which case he would be disqualified from serving as president). But remember that more than a third of Democrats subscribe to the even more outlandish theory that the Bush administration knew about the attacks of September 2001 in advance.

These factions are incapable of intelligent conversation with each other, or indeed with anybody else. But the important thing to remember is that the political significance of the cultural jihadists is smaller than the noise they generate. They will not decide the issue.

Mr Obama's health proposals are not in trouble because conservative Republicans oppose them. Conservative Republicans were always going to oppose them. They are in trouble because moderate Republicans oppose them, and even more because many moderate Democrats also have doubts.

Mr Obama has to persuade centrists – the voters who elected him president – to support health reform. It is as simple as that. If he brings moderates and independents on board, reform will succeed. If he fails, the effort will either be abandoned or, more likely, the plans will be watered down.

The town hall protesters, with their “death panel” hysterics and posters depicting Mr Obama with a Hitler moustache, may help push centrists back to the Obama camp. If not, they should. So far, though, Mr Obama's lamentable salesmanship has pushed harder the other way. Hindered no doubt by the fact that there is still no finished plan to sell, he has failed to come up with a plausible line to put to the country.