WASHINGTON — New England’s shrinking Republican delegation in Congress is moving toward the brink of political extinction in November with Donald Trump at the top of the party’s ticket.

Only four Republicans remain in New England’s 33-member congressional delegation, and three are in competitive races this fall. The other, four-term Senator Susan Collins of Maine, doesn’t face re-election this year.

The so-called Rockefeller Republicans who once represented the region became a dying breed in the past few decades as the party moved to the right. Trump, with his controversies and bombastic demeanor, has complicated what was already a difficult task of getting re-elected for the region’s party members.

“Bottom line: I want them to win badly. It’s just going to be so difficult,” said Christopher Shays, a Republican House member from Connecticut from 1987 until he was defeated in 2008. Trump’s candidacy “is a disaster for the Republican Party,” he said in an interview.

Losses by Republican Sen. Kelly Ayotte and Rep. Frank Guinta, both of New Hampshire, and Rep. Bruce Poliquin of Maine could leave Collins as the only member of her party in Congress from the six New England states: Connecticut, New Hampshire, Vermont, Rhode Island, Maine and Massachusetts.

Republicans aren’t seen as competitive in the region’s 29 Democratic-held House and Senate seats on the November ballot.

“New England congressional Republicans have been in a perilous political state for some time,” said Julian Zelizer, a Princeton University professor of history and public affairs. But the prospect of only one House or Senate member from the entire region “would be really amazing,” he said.

There is some precedent. With Shays’ loss, New England Republicans suffered a complete wipeout in House races in 2008, although they still had members of the U.S. Senate. Two years later, the return of former New Hampshire congressman Charlie Bass and Guinta’s election in New Hampshire re-established the Yankee Republican presence in the chamber – barely.

What makes this year’s New England races even more dramatic is that Republicans otherwise currently hold their largest U.S. House majority since 1928 — 247 seats to 186 — because of their large numbers in the South and other areas of the U.S. Two vacant seats, formerly held by Democrats, are vacant.

Fighting for survival, the three incumbents’ campaign strategies when it comes to Trump have been scattershot so far.

Ayotte, who like Guinta first faces a Sept. 13 Republican primary, says she will vote for Trump – who won the New Hampshire primary – but isn’t actually endorsing him. She is maintaining her position even after Collins wrote a column in The Washington Post saying she won’t back Trump.

“Ayotte has engaged in political gymnastics,” said Wayne Lesperance, a political science professor at New England College in Henniker, N.H. Trump will affect turnout and Ayotte needs his backers to pull the lever for her, while she’s also trying to attract independent voters, the professor said.

Democratic Gov. Maggie Hassan, who would face Ayotte in a general election, is hitting the senator for not denouncing Trump. At the same time, an Ayotte Republican primary opponent, Jim Rubens, endorsed Trump and criticizes her for not doing so. “Ayotte’s affinity clearly lies with Hillary Clinton, not our Republican nominee,” he jabbed in a statement.

In his race in New Hampshire, Guinta has been clear that he supports Trump and will vote for him. He has called on a primary opponent, Rich Ashooh, to back Trump more forcefully. Ashooh’s campaign general counsel Jay Flanders said the challenger believes “it is not his job to defend” Trump and will focus on his own campaign.

Guinta’s Democratic opponent, Carol Shea-Porter, is a former congresswoman who is running again for the seat that has swung between her and Guinta since she first won it in 2006. She has hit both Guinta and Ashooh on Trump. Her campaign spokeswoman, Naomi Andrews, said in a statement that their silence regarding “Trump’s ugly, racist attacks” denotes “tacit approval.”

“New Hampshire citizens now know they would not be able to count on either of them for moral leadership,” Andrews said.

Beyond Trump, Guinta also is dealing with the fallout of a campaign finance scandal. The Federal Election Commission concluded that he accepted $355,000 in illegal contributions from an account in his parents’ name. He apologized for what he said was a reporting error, signed a settlement with the FEC and agreed to pay a fine and refund the money.

In Maine, Poliquin has been dodging the Trump question, declining to answer questions about his party’s nominee. His election in 2014 put the seat in the Republican column for the first time in 20 years.

Candidates normally don’t have to decide whether to back their own party’s presidential contender, said James Melcher, a political science professor at the University of Maine-Farmington.

“The Trump campaign has forced Republican candidates to risk alienating blocs of voters on either side in making that decision,” Melcher said. “Poliquin has tried to straddle the question, but how long will he be able to do that?”

Poliquin’s Democratic opponent, Emily Cain, has seized on it.

“Mainers value doing the right thing regardless of party,” Cain said in an emailed statement. “Congressman Poliquin’s lack of independence is highlighted by the comparison to Sen. Collins, whose stance on Donald Trump casts a harsh light on his calculated political strategy.”

Collins, while not backing Clinton, said she won’t support Trump and described him in her column as “unworthy” of the presidency and someone who doesn’t “reflect historical Republican values.”

“Instead of a coattail effect for this presidential candidate, New England Republicans face the opposite effect.” said Lesperance, the political science professor at New England College in Henniker, N.H.