DENVER (AP) -- A Colorado lawmaker sponsoring an Arizona-style crackdown on illegal immigration says he's backing off the effort because he worries it would cost taxpayers if it is challenged in court.

Republican Rep. Randy Baumgardner told The Associated Press on Wednesday that he plans to ask fellow lawmakers to effectively kill the bill.

The measure would have allowed police to arrest illegal immigrants without warrant if law enforcement had probable cause to believe they were in the country illegally. It also would have required immigrants to always carry their documents and made it illegal for undocumented immigrants to work in Colorado.

Baumgardner said some aspects of the bill "could be construed as unconstitutional," leading to legal challenges. He said he doesn't know whether he'll bring the proposal back another year.

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