Don't expect Republicans to take a target off House Minority Leader Nancy Pelosi's back in this year's midterms.

Forty-five percent of registered voters say they are less likely to support a candidate who backs the California Democrat for House speaker should her party win a House majority in November, according to an NBC News/Wall Street Journal poll released Thursday. Only 21 percent say they are more likely to vote for someone who supports Pelosi's speakership, while 32 percent say it will make no difference.

Republicans have aimed to capitalize on poor nationwide public opinion of Pelosi as they try to prevent Democrats from winning the 23 GOP-held seats needed to take control of the House. They have focused in large part on Pelosi's goal of reversing some of the Republican tax cuts passed in December.

Though Pelosi's poll numbers are poor, both Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan also have seen dismal approval ratings. Only 11 percent of registered voters responding to an NBC News/WSJ poll last year had a positive view of McConnell, while 24 percent said the same about Ryan.

Attacks on Pelosi could weigh on some Democratic House candidates this year. But several candidates have distanced themselves from the 78-year-old congresswoman. At least 20 Democrats — many of them trying to win seats in GOP-leaning districts — have either outright opposed Pelosi or declined to support her.

Democratic Rep. Conor Lamb, who won a House election in a red pocket of Pennsylvania in March, refused to back Pelosi as national Republicans ran attack ads about the Democratic leader. Democrats running for GOP-held seats such as Mikie Sherrill in New Jersey's 11th District and Dan McCready in North Carolina's 9th District have called for new party leadership.

Last month, Pelosi said she did not care if candidates refuse to back her, "if they have to do that to win an election."

"I'm all for winning," she added.

The NBC/Wall Street Journal survey also suggests Democratic candidates could have issues if they associate with two other party luminaries: Bill and Hillary Clinton. Twenty-seven percent of voters responded that they are very uncomfortable with supporting a candidate backed by the former president, compared with only 9 percent who say they are enthusiastic.

Thirty-seven percent answered that they are very uncomfortable with backing a candidate endorsed by the former first lady and secretary of State, versus 9 percent who say they are enthusiastic. The Clinton family is expected to take only a limited role in campaigning for Democrats this year.

Those figures look even worse for President Donald Trump, who plans to take an active role in campaigning for Republican Senate candidates this year. Twelve percent of voters responded that they would be enthusiastic about a candidate endorsed by Trump, but 38 percent answered that they would be very uncomfortable.

The poll also found that 31 percent say they are very uncomfortable with backing a candidate who supports tariffs on countries such as Canada, Germany and China.

The NBC/Wall Street Journal poll surveyed 900 registered voters from June 1 to June 4 and has a margin of error of plus-or-minus 3.3 percentage points.