DENVER – Mitt Romney’s presidential campaign has been savaging what it calls President Barack Obama’s “unhealthy” obsession with “green jobs.” The Republican challenger criticizes the government program that propped up solar manufacturer Solyndra, and he mocks Obama’s vision of a boom in employment, citing a European study to argue that new solar or wind-energy positions would destroy jobs elsewhere.

But when a campaign spokesman said last week that Congress should let a tax break for wind energy producers expire at the end of the year, some Republicans were concerned the candidate had gone too far.

Republican Rep. Tom Latham, R-Iowa, noting that nearly 7,000 Iowans work in the wind industry, assailed the Romney campaign for “a lack of full understanding of how important the wind energy tax credit is for Iowa and our nation.” Iowa’s senior senator, Chuck Grassley, told reporters he didn’t believe Romney really opposed the extension, and he joined five other GOP lawmakers in voting for it in the Senate Finance Committee.