This item by J.P. Green was first published on April 19, 2011.
Alan I. Abramowitz and Nate Silver agree that Dems have a good chance to win back a majority in the U.S. House of Representatives next year, which should be cause for some concern among smarter Republicans. Here’s Abramowitz, from his current column at Larry J. Sabato’s Crystal Ball:

Democrats would only need to pick up 25 seats in 2012 to get to the magic number of 218 that would give them control of the House-assuming that all of their members supported the Democratic candidate for Speaker. That’s hardly an insurmountable number. In fact, two of the last three elections, 2006 and 2010, have produced bigger swings, and 2008 came close.
Despite the recent volatility of House elections, some astute political observers are giving the Democrats little or no chance of regaining control of the House in 2012. For example, last December, Republican pollster Glen Bolger went so far as to “guarantee” that the GOP would maintain its House majority even if President Obama were to win a second term. And just last month, respected political handicapper Charlie Cook agreed that a Democratic pickup of 25 or more seats in the House was highly unlikely.
Both Bolger and Cook cited the relatively short coattails that winning presidential incumbents have had in recent years as a major obstacle to big Democratic gains in the 2012 House elections. In the past 40 years, the largest number of House seats gained by the winning incumbent’s party was 16 in 1984, a year in which Ronald Reagan won reelection by a landslide. You have to go all the way back to 1964 to find an election in which the winning incumbent’s party gained at least 25 seats in the House.
Notwithstanding these predictions and the historical record, however, there are three reasons to believe that Democrats have a decent chance of taking back control of the House in 2012. First, as a result of their big gains in 2010, Republicans will be defending a large number of seats in House districts that voted for Barack Obama in 2008; second, many of those districts are likely to vote for Obama again in 2012 because of the difference between the presidential and midterm electorate in the current era; and third, Republican incumbents in these Obama districts will be at high risk of losing their seats if Obama wins because straight-ticket voting is much more prevalent now than it was 30 or 40 years ago.

Further, adds Abramowitz,

…There are 60 Republicans in districts that were carried by Barack Obama in 2008 including 15 in districts that Obama carried by at least 10 points. In contrast, there are only 12 Democrats in districts that were carried by John McCain in 2008 and only six in districts that McCain carried by at least 10 points.

As for the GOP’s supposed edge in redistricting, Abramowitz notes:

Of course before the 2012 congressional elections take place, House districts will be redrawn based on the results of the 2010 Census. In states where Republicans control redistricting-and the number of such states grew considerably as a result of the 2010 midterm elections-GOP legislatures may be able to redraw the lines to protect potentially vulnerable Republican incumbents. However, the ability of Republican legislatures to protect their party’s House incumbents may be limited by the dramatic increase in the past decade in the nonwhite share of the population in many states. For example, while Republicans will control redistricting in Texas, which is gaining four House seats, more than any other state, most of the population growth in Texas has been because of the rapid increase in the Hispanic population. At least one, if not two, of the new Texas House districts are likely to go to Hispanics.

Abramowitz also cites the increased turnout, over the mid terms, of Obama-friendly constituencies in a presidential election, particularly Latino voters, who are growing even faster than expected, according to the latest census data. But he believes the Dems strongest card may be the rising trend toward straight-ticket voting in recent years. Abramowitz stops short of predicting a Dem takeover of the House, but he calls it a “realistic” possibility, especially if Obama wins a “decisive victory” in ’12.
Nate Silver sees the budget fight and the vote on GOP Rep. Ryan’s draconian budget proposals as a potential net plus for Democratic congressional candidates. Silver explains in a recent five thirty eight post,

So far, no polls have been conducted on Mr. Ryan’s budget as a whole. But — although voters will like the deficit reduction it claims to achieve (several outside analysts have questioned the bill’s economic findings) — a couple of its individual elements figure to be quite unpopular. In particular, the bill includes substantial changes to Medicare and Medicaid — changes that many voters tell pollsters are unacceptable. And it would cut the top tax rates, when polls usually find that most Americans want taxes on upper-income Americans to be raised rather than lowered.

Silver also believes that the Republicans’ prospects for a senate takeover next year are overstated. Echoing Abramowitz’s point about the decline in split-ticket voting, he sees the vote on Ryan’s proposals as a potential game-changer for the House:

…One possible consequence of the vote is that it could tie the fate of Mr. Obama and the Democrats in Congress more closely together. In the past, presidents have rarely had substantial coattails when running for a second term; Bill Clinton’s Democrats won just 9 seats in the House in 1996, for instance, even though he beat Bob Dole overwhelmingly. In 2010, however, the share of the vote received by Democrats running for Congress was very strongly correlated with support for Mr. Obama, and today’s vote could deepen that connection, making it less likely that voters will return a divided government again.

When two of the sharpest political data analysts agree that the House may be up for grabs, the DNC and Dem contributors should take note and invest accordingly. Of course there is a difference between Dems having a decent chance to win back a House majority and the probability of it happening. For the moment, however, The President appears to be moving into solid position to leverage the trend toward straight-ticket voting for the benefit of the Party. With a favorable break or two on the economy, the possibility of a Dem takeover of the House could morph into a good bet.