Many Republican candidates in the November congressional elections are trying to capitalize on a wave of popular resentment against illegal immigration. But there’s a catch: Both their Republican president, George W. Bush, and many business leaders who have been generous campaign contributors see immigrant labor (including the illegal variety) as an essential ingredient in the labor market.

True, some Republican candidates are distancing themselves from the president because of his stubborn stay-the-course policy on the Iraq war in the face of rising anxiety about the seemingly endless conflict and questions about its justification and management.

But political contributions are something else. Several business groups that normally support Republicans take a dim view of congressional candidates who favor punitive action against illegals and oppose efforts to ease their way toward citizenship.

The Wall Street Journal reports that business groups including the Associated General Contractors of America and the National Roofing Contractors Association say they will cut or eliminate campaign contributions to some candidates who take a hard line on immigration.

The Journal quotes a Los Angeles Times report of a confrontation be-tween Rep, Gary Miller, a California Republican, and Cyndi Smallwood, who owns a landscaping company in Riverside, Calif. The newspaper said she told him she was having trouble finding workers, even at the prevailing hourly rates of $34 for skilled and $14 for unskilled workers.

According to the Times, Mr. Miller doubted her story and placed a mock “help wanted” ad in local newspapers. It gave Ms. Smallwood’s name, address and telephone number and asked, “Want to make up to $34/hour?” She was quoted as saying that her phone and fax machine were loaded with complaints and curses about her pro-immigration position.

One flaw in the anecdote was that it didn’t say whether the ad produced any job applicants. It turns out that she did get about 30 resumes the morning the Times story appeared. But she still relies on immigrant labor and wants restrictions eased. Critics complain that she is a pro-immigration activist and has lobbied for reform.

So the conflict goes on. Landscape gardening, like home construction, agriculture and the tourism industry, to name a few, depend on immigration for a supply of cheap labor – yes, for jobs that American citizens often won’t take. And public outrage continues to be fanned by conservative pundits, broadcast talk shows including a CNN anchor, and congressional candidates looking for an inflammatory issue to divert attention from Iraq.

The November election outcomes will provide a measure of which side is coming out ahead in what amounts to a major public debate.