FACTBOX: Senate Democrats will need some Republican help

(Reuters) - With a close Minnesota race still undecided, Democrats will hold no more than 59 seats in the new 100-member U.S. Senate that convenes on January 6.

That means Democrats will need the help of at least a few Republicans to hit the 60 votes required to clear procedural roadblocks known as filibusters.

Here's a look at some Senate Republicans who have worked with Democrats in the past:

* John McCain of Arizona, the failed U.S. presidential candidate, has earned a reputation for bucking party leadership, including on a bipartisan bill that would have revamped U.S. immigration laws. Unlike many Republicans, McCain also favors aggressive action to stem global warming.

* Susan Collins of Maine has opposed Republican leaders by voting to maintain a ban on oil drilling in protected areas of Alaska and against conservative social issues, like banning same-sex marriage and imposing new limits on abortion. She also has voted in favor of expanded stem-cell research and providing illegal immigrants a path to U.S. citizenship.

* Olympia Snowe, also of Maine, has broken ranks with many fellow Republicans in voting to increase the federal minimum wage. Like Collins, she has opposed many conservative social initiatives. She also breached Republican doctrine in 2004 when she argued for applying "pay as you go" budget rules to tax cuts as well as spending increases.

* Arlen Specter of Pennsylvania was instrumental in defeating Republican President Ronald Reagan's nomination of Robert Bork to serve on the U.S. Supreme Court. More recently, he opposed limits Bush sought on medical malpractice lawsuits and butted heads with the Bush administration on warrantless electronic surveillance.

* George Voinovich of Ohio worked to narrow the size and cost of Bush's signature tax cuts and voted against some Republican budget plans. In 2005, Voinovich spoke out against Bush's choice of John Bolton to be U.S. ambassador to the United Nations.

* Conversely, some centrist Democrats cannot be counted on to always vote with their party. Among them are Mary Landrieu of Louisiana, Ben Nelson of Nebraska, Max Baucus of Montana and Blanche Lincoln of Arkansas.

(Sources: Reuters, The Almanac of American Politics)

(Reporting by Richard Cowan; editing by David Alexander and Mohammad Zargham)