Barack Obama’s massive campaign operation has generated a spike in Democratic voter registration in battleground states and competitive House districts, prompting political experts to predict that Obama will bring a crowd of Democrats into office on his coattails.

Sen. Obama (D-Ill.) is also expected to help Democratic candidates in states where he leads in the polls and voters are allowed to save time and vote for every Democrat (or Republican) on the ballot with a single mark of the ballot. Straight-party voting is allowed in several states where Obama has poured in money and campaign workers: Indiana, Iowa, Michigan, New Mexico, Pennsylvania, West Virginia and Wisconsin.

That could pose a major problem for Rep. Jon Porter (R-Nev.), who squeaked into office with 49 percent of the vote in 2006 and now faces a stiff challenge from Democratic state Sen. Dina Titus.

Since the beginning of the year, the number of registered Democrats in his district has shot up nearly 50,000. The number of Republicans, however, increased by 18,000, according to data compiled by Nevada’s secretary of state.

“I think it will have a tremendous effect,” said Paul Kincaid, spokesman for the Nevada Democratic Party.

Democrats also enjoy a dramatic advantage in voter registration in New Mexico, which has an open Senate seat and three open House seats. Democrats increased party registration in the state by 55,000 since 2006. Republicans, meanwhile, increased their numbers by 16,000.

Democrats have a significant registration advantage in New Mexico’s 1st and 2nd congressional districts, which were held by Republican Reps. Heather Wilson and Steve Pearce, respectively, in the 110th Congress.

Democratic candidates are poised to capture both seats. Republicans in Washington have written off their chances in the 2nd, where candidate Ed Tinsley has decided to pull his ads off the air during the final days of the campaign, even though President Bush carried the district with 58 percent of the vote in 2004.

Timothy Krebs, a political science professor at the University of New Mexico, said that new voters would most likely pull the lever for a straight-party vote to save time after standing in line to vote.

“I think there could be a coattail effect,” said Krebs, who noted that Democratic candidates Martin Heinrich and Harry Teague are leading in the polls in the 1st and 2nd congressional districts, traditionally Republican territory. The 3rd district, held by Rep.-turned-Senate candidate Tom Udall (D), is expected to stay in Democratic hands.

Obama has also made a concerted effort to register voters in North Carolina, where 21 percent of residents are African-American.

Democratic registration has jumped nearly 300,000, while Republican registration has increased by about 70,000. Voters in North Carolina are also allowed to vote straight-ticket on down-ballot races, although they must vote separately for the presidential candidates.

“The number of new registered voters and number of new Democrats in North Carolina has to bode well for other Democratic candidates,” said Thomas Carsey, a professor of political science at the University of North Carolina at Chapel Hill.