Nancy Pelosi is unlikely to win her gavel back, experts say.  (Melina Mara/THE WASHINGTON POST)

Stuart Rothenberg writes today:

 Democratic retirements and some weaker than expected candidates in places like California and Pennsylvania have limited the party’s upside potential, forcing Democrats to defeat nearly two dozen GOP incumbents if they are going to net enough seats to re-install House Minority Leader Nancy Pelosi as the next speaker.

That echoes a Cook Political Report analysis of two weeks ago.

“The Cook Political Report is adjusting its House forecast from a Democratic gain of between five and 15 seats to a minimal net partisan change, most likely between two seats for Republicans and eight for Democrats,” Cook wrote.

Democrats need 25 seats to win back the House. Given that President Obama is headed into a very close reelection fight in a bad economy, and Republican control of redistricting in many key states helped the party shore up vulnerable members, both Stuart Rothenberg and Cook Political Report argue that a “wave” like the one that swept Republicans into power two years ago is unlikely.

Even if Democrats won the 25 seats Cook classifies as lean or likely Democratic, along with all 24 toss-up races, they would still need to win 13 out of 18 lean Republican seats to take control.

Generic congressional ballots show Democrats with a slim lead over Republicans. In 2010, the GOP did not develop a major lead in that polling until mid-August. House Speaker John Boehner (R-Ohio) has himself said that Democrats have a “one-in-three” chance of taking his gavel away.

“In the latest congressional generic ballot voters prefer Democrats over Republicans for Congress and three quarters of our Red to Blue candidates outraised their Republican opponent so the Republican Majority is in jeopardy,” said Democratic Congressional Campaign Committee spokesman Jesse Ferguson.

Democrats definitely have the advantage in this cycle; Republicans have more members period and more vulnerable members. Redistricting did not give them many new opportunities. But right now, 25 looks like too steep a hill to climb.