Once upon a time Republicans could count on the support of small business owners, but that era may soon be over.

A key test of small business sentiment is shaping up in the Missouri Senate race where two small business advocacy groups are endorsing opposing candidates. Republican Sen. Jim Talent now trails Democratic state auditor Claire McCaskill by three points, a statistical dead heat, according to the latest Reuters/Zogby poll.

Lloyd Chapman, president and founder of the American Small Business League, issued a statement today urging small business owners to vote for McCaskill. "Stop listening to Republican pro-small business rhetoric. This party intends to eliminate the Small Business Administration and all federal small business programs," he said.