LIGHTLY SETTLED by people but thickly planted with corn, Iowa wields outsize influence in national politics. Presidential contenders from both parties woo voters in Iowa’s first-in-the-nation presidential caucuses by promising everything from crop subsidies to ethanol mandates. The state’s more recent status as a swing state — President George W. Bush won in 2004, President Obama in 2008 — has added to its clout, even if the last census reduced its electoral votes from seven to six.

So there’s no surprise in Mr. Obama’s three-day bus tour of the state this week: He munched pork, downed beer and decried Congress’s failure to pass a new, five-year farm bill. According to Mr. Obama, the record drought ravaging corn farms in Iowa and elsewhere strengthens the case for the legislation. “Now, the best way to help these states is for Congress to act,” he said. “They need to pass a farm bill that not only helps farmers and ranchers respond to natural disasters but also makes necessary reforms and gives them some long-term certainty.”

Actually, almost nothing in the farm bill would affect drought-stricken farms one way or the other. About 80 percent of the bill’s nearly $1 trillion price tag (over 10 years) reflects the cost of food stamps, an essential part of the safety net. The rest is largely a grab bag of subsidies for producers, with the biggest benefits for the largest farms, i.e., those least vulnerable to drought and other risks. Existing law already provides subsidized crop insurance for more than 80 percent of the nation’s farmland; many dairy farms, too, enjoy subsidized insurance against rising feed costs.

There are, indeed, modest reforms in the bill; it eliminates costly and wasteful “direct payments” but offsets that by expanding crop insurance subsidies. The bill would protect producers so much that they might lose their incentive to use land prudently, thus raising the potential for losses in the next drought. To really help livestock farms, which are most hurt by rising corn prices, Mr. Obama should heed elected officials in both parties — including Gov. Martin O’Malley (D) of Maryland — who are asking his administration to waive ethanol mandates so that more grain would be available for animal feed.

Mr. Obama is also promising Iowans an extended tax credit for wind-energy production, which expires at the end of this year but to date has helped Iowa generate 20 percent of its electricity from that source. Not incidentally, Iowa farmers get $11 million a year renting their land to windmill operators. Mr. Obama argues that this is job-creating clean energy, and he is hardly alone in that. Supposedly fiscally conservative, free-market Republicans such as Rep. Steve King of Iowa tout the tax credit, which costs the Treasury well over­ $1 billion a year. Of course, that money might have created even more jobs elsewhere, or saved more carbon emissions, if the government did not steer it into Iowa wind farms.

Republican challenger Mitt Romney deserves credit for opposing an extension to the wind subsidy, a position that could hurt him in Iowa and in Colorado, another windy swing state.

Too bad the GOP candidate engaged in a bit of energy pandering himself the other day, promising coal miners in Ohio that “we’re going to . . . save your jobs.” So what if replacing coal plants with inexpensive natural gas would rapidly cut greenhouse gas emissions? Ohio, too, is a swing state, whose 18 electoral votes are three more than Iowa and Colorado put together.