Washington ? New federal overtime regulations will not take effect automatically in 18 states, provoking widespread confusion among state officials, employers and workers, and sparking political battles over how to respond.

Those states have their own overtime requirements, some of which mirror the old federal rules being replaced in August. Legislative action is required in some states to make changes, complicating an already complex and politically turbulent issue in an election year.

“It’s absolute craziness,” said Camille Olson, a labor lawyer with the firm Seyfarth Shaw in Chicago.

The Labor Department regulations issued last month will go into place automatically in 32 states and the District of Columbia, according to a Seyfarth Shaw analysis. Elsewhere, it is not so simple.

“We’re in a wait-and-see mode,” said John Andrew, chief of the Labor Standards Bureau in Montana’s Labor and Industry Department.

New federal definitions of some white-collar jobs would not apply in Montana without changes to state law or state administrative rules, he said. The Legislature may have to act, but it does not meet again until January.

The federal rule is a minimum standard. States can have their own requirements, but they cannot be less generous with overtime eligibility.

The rule rewrites definitions of white-collar workers exempt from overtime pay under the 1938 Fair Labor Standards Act.

Labor Department officials say the changes were needed for clarification and to reduce the number of workers’ lawsuits against employers. The rule, which takes effect Aug. 23, will exempt about 100,000 workers now eligible for overtime pay, officials said. Democrats and labor unions say the number will be much higher.

Underscoring the election-year importance of pocketbook issues, the Republican-controlled Senate voted 52-47 to require that overtime eligibility be guaranteed for all workers who currently qualify. Democrats want to force a vote in the House; GOP leaders acknowledge it will be close.

Other states where the federal rules will not take effect automatically: Alaska, Arkansas, California, Colorado, Connecticut, Hawaii, Illinois, Kentucky, Maryland, Minnesota, New Jersey, North Dakota, Oregon, Pennsylvania, Washington, West Virginia and Wisconsin.