BY SAM HANANEL

Associated Press

WASHINGTON

--The AFL-CIO says it has registered more than 450,000 new voters from union households over the past 18 months, part of an ambitious push to swell the ranks of Democratic-leaning voters and help President Barack Obama win reelection.

The tally includes about 68,000 new voters in Ohio--one of the most contested battleground states this year--and thousands of other union-friendly voters in swing states like Colorado and Nevada.

"That's an amazing number," said Paul Beck, a political science professor at Ohio State University. "In an era of declining union membership, one wouldn't think there would be many new targets out there."

Obama defeated Republican John McCain by a little more than 200,000 votes in Ohio in 2008 out of about 5 million votes cast in the state.

Voters from union households have traditionally favored Democratic candidates. That trend is expected to continue this year in light of high-profile efforts by Republican leaders to weaken collective bargaining rights in Ohio, Wisconsin, Indiana and other states.

In 2008, exit polls showed 59 percent of voters who lived in union households backed Obama, while 39 percent supported McCain. Union household voters split similarly in the previous two presidential elections.

"This is the first time we've made this big an effort to increase registration," said Mike Podhorzer, AFL-CIO political director. "We're really proud that more union members are going to be engaged. Whoever they vote for, the fact is we're increasing civic participation."

Podhorzer said the plan began in March 2011, when the labor federation began matching lists of union household members with voter registration files from every state. It then identified about 2.3 million people living in households of active and retired union members who were not registered to vote.