The line between the Republican establishment and the Tea Party has blurred. That spells trouble for the GOP in the long run. Possibly this year, more likely in 2016.

It might not look like it right now. The Republican establishment, which has been on the defensive since the Tea Party emerged in 2009, is on a roll. Establishment candidates have won contested primaries in North Carolina, Florida and now Kentucky and Georgia. Republican voters seem to be turning away from the kinds of fringe candidates they went for in 2010 and 2012, like Christine O’Donnell in Delaware (“I am not a witch”) and Todd Akin in Missouri (“legitimate rape”). Candidates like that cost Republicans their chance to take back control of the U.S. Senate.

So this year, the party stands a good chance of taking over the Senate and expanding its majority in the House of Representatives. The Obama era is over!

Oh, wait. Barack Obama is still president. And the Republican Party’s long-term problems are far from resolved. For one thing, the party’s good fortune this year is mostly the result of temporary advantages: — Democratic Senate seats up for grabs in strongly Republican states; Democrats defending House seats they won narrowly in 2012.

For another thing, the Tea Party is not exactly vanquished. Establishment candidates may be winning primaries — but that’s because most of them have moved right and pre-empted the Tea Party’s message.

Thom Tillis, who won the Republic Senate primary in North Carolina, is a good example. Tillis was the establishment favorite, endorsed by the U.S. Chamber of Commerce, in the primary. But he had to lurch to the right to fend off Tea Party challengers, denying human-caused climate change, opposing an increase in the federal minimum wage and advocating the elimination of the Department of Education.

In Georgia, the Republican Senate contenders tried to outrun one another toward the right — challenging their rivals’ conservative credentials, calling for the privatization of entitlements, opposing immigration reform and denouncing abortion rights. Democrats in both states will use those issues to paint their Republican opponents as extremists.

Incumbent Republicans once favored by the Tea Party are also finding themselves challenged from the right. House Majority Leader Eric Cantor (R-Va.), expected to succeed Representative John Boehner (R-Ohio) as speaker, is facing a troublesome Tea Party opponent in his House re-election campaign. Cantor’s party chairman in the district was overthrown by Tea Party activists.

Senator Marco Rubio (R-Fla.) has angered conservatives by advocating immigration reform. He tried to make up for it by defying the scientific consensus on climate change. “I do not believe that human activity is causing these dramatic changes to our climate the way these scientists are portraying it,” Rubio said on ABC

Republicans have moved so far to the right that some of the party’s leading figures have found it necessary to break with conservatives. Former Florida Governor Jeb Bush and New Jersey Governor Chris Christie, as well as Rubio, have endorsed immigration reform. Senator Rand Paul (R-Ky.) has criticized restrictions on voting rights, saying, “I think it’s wrong for Republicans to go too crazy on this issue because it’s offending people.” Mitt Romney, the party’s 2012 presidential nominee, says he parts company “with many of the conservatives in my party on the issue of the minimum wage” because “we ought to raise it.”

Republicans who oppose raising the federal minimum wage cite as Holy Scripture a Congressional Budget Office memo estimating that increasing it could eliminate 500,000 jobs — but also boost earnings for 16 million workers.

They hold no such reverence for the National Climate Assessment, prepared by several hundred scientific and technical experts, that warns “harm to the nation will increase substantially in the future unless global emissions of heat-trapping gases are greatly reduced.’’

Still, conservatives are not satisfied. Conservative activists, alarmed by the resurgence of the party establishment, met last week near Washington to organize the Conservative Action Project. They are demanding strict opposition to illegal immigration, same-sex marriage and abortion. “Conservatives ought not to delude themselves that if Republicans win the Senate majority, it will somehow be a conservative majority,” warned L. Brent Bozell, president of the Media Research Center.

There is likely to be pressure on the GOP to change its platform position calling for a constitutional amendment that defines marriage as only between one man and one woman. If the party doesn’t change, it’s likely to write off the support of the millennial generation. If it does change, religious conservatives will quit the party in protest.

Republicans are already writing off the support of minorities. Asian-Americans, the nation’s fastest-growing minority group, include a lot of business-oriented voters. Nonetheless, Gallup reports that they have shifted more strongly toward the Democratic Party than any other racial or ethnic group.

The New York Times recently examined party unity on 11 issues where Democrats and Republicans take opposite positions, including climate change, immigration reform, the Affordable Care Act, same-sex marriage and gun control. The Times found that 61 percent of Democrats agreed with their party on at least eight issues. Only 42 percent of Republicans agreed with their party on at least eight issues. Democrats are now more unified than Republicans.

It’s finally happening. The Republican Party is becoming too extreme for Republicans.

PHOTO (TOP): Senate Republican Leader Senator Mitch McConnell (R-Ky.) speaks to supporters during a campaign stop at the Lexington Airport in Lexington, Kentucky, May 19, 2014. REUTERS/John Sommers II

PHOTO (INSERT 1): Thom Tillis, (3ndR), speaks with supporters before a debate between the four top-polling Republican candidates in North Carolina for the U.S. Senate, at Davidson College in Davidson, North Carolina April 22, 2014. REUTERS/Davis Turner

PHOTO (INSERT 2): Senator Rand Paul (R-Ky) is seen on a screen as he introduces Senate Republican Leader Sen. Mitch McConnell (R-Ky.) to a crowd of campaign supporters after McConnell defeated Tea Party challenger Matt Bevin in the state Republican primary elections in Louisville, Kentucky, May 20, 2014. REUTERS/John Sommers