(CNN) – Republican candidates running for office sometimes use Nancy Pelosi's name like a curse word.
Perhaps they've seen polling that indicates the House Democratic leader is the best known but least liked congressional leader, as indicated by a new Gallup survey released Wednesday.
According to the poll, 48% of Americans have an unfavorable opinion of Pelosi, while 31% view her in a favorable light.
Former Gov. Mark Sanford, for example, plans to solo debate against Pelosi's positions Wednesday as he campaigns for a special congressional election in South Carolina, saying his opponent, Elizabeth Colbert Busch, has only agreed to one debate.
"Because my opponent is refusing joint appearances to answer questions about where she stands on the issues, all we can assume is that she is going to be a reliable vote for the Pelosi-Obama agenda, were she to be elected," Sanford said in a statement.
Colbert Busch's team responded, saying the Democratic candidate is "spending her time with real people who support her campaign."
Of the people surveyed for the poll, 79% have some knowledge of Pelosi, while 21% either have no opinion about the congresswoman from California or because they have never heard of her.
According to the poll, none of the other three congressional leaders have particularly strong marks. In fact, none of them top 31% in their favorable ratings, and all four have higher unfavorable ratings than favorable.
House Speaker John Boehner has an unfavorable rating of 41%, slightly below that of Pelosi, his predecessor. Thirty-one percent have a positive opinion about the Republican from Ohio. Twenty-eight percent have no opinion.
On the Senate side, just over a quarter of Americans–27%–have a favorable opinion of Majority Leader Harry Reid, while 38% view him unfavorably and 35% have no opinion. Republican leader Mitch McConnell, who's up for re-election next year, has a 26% favorable rating and a 34% unfavorable rating. Forty percent have no opinion on the lawmaker from Kentucky.
For the survey, Gallup interviewed 1,012 adults by telephone from April 11 through April 14. The sampling error is plus or minus four percentage points.
– CNN's Ashley Killough contributed to this report.