Mark Penn: Ryan's refusal to retire is impacting congressional GOP's approval ratings

Prominent pollster and ex-Clinton aide Mark Penn said on Thursday that House Speaker Paul RyanPaul Davis RyanPelosi, Schumer: Trump 'desperate' to put focus on immigration, not health care Trump urges Dems to help craft new immigration laws: ‘Chuck & Nancy, call me!' Sanders, Harris set to criss-cross Iowa MORE's (R-Wis.) refusal to retire from his post is negatively affecting congressional Republicans' approval ratings. 

"The Republicans in Congress also have a problem because they don't have a leader. They have a leader who quit. Whoever heard of going to an election with a leader who quit, but won't hold an election for a new leader?" Penn told Hill.TV's Krystal Ball and Buck Sexton on "Rising." 

"So I think the Republicans, at least in Congress, are hitting themselves...because they don't have a united message or group," he added. 

Congressional Democrats lead Republicans on the generic ballot ahead of November's midterm elections, according to a new Harvard CAPS/Harris poll

The survey found that 45 percent of those polled said they prefer congressional Democrats, while only 36 percent said they prefer Republicans.

The Harvard CAPS/Harris Poll online survey of 1,448 registered voters was conducted June 24-25. The partisan breakdown is 37 percent Democrat, 32 percent Republican, 29 percent Independent and 2 percent other. 

Ryan announced in April that he would be retiring at the end of this Congress, ending his speakership. 

The Republican congressman has pushed back on calls to resign ahead of the midterms in an effort to help unify the party. 

“There’s so much more I can do to keep continuity. We have a great leadership team. There’s so much more I can do to help keep this majority," Ryan said in an interview with NBC's Chuck Todd last April. 

— Julia Manchester