If the last Congressional midterm election was a wave, this year may be more of a ripple.

None of the nationally recognized political prognosticators expect a landslide election in either the House or Senate, though the GOP is expected to do well in both chambers.

Despite critical stories and negative poll numbers for President Obama and many Democratic candidates, the overall picture calls for only modest gains for the GOP.

One major reason there is no wave this year is structural. There are a limited number of truly competitive seats in the House and Senate, making it nearly impossible for either party to win overwhelmingly.

In the House, all 435 seats are on the November ballot, but only a dozen or so are truly vulnerable, or listed as “toss up,” by the race rating experts. Most of those are Democratic seats, but Republicans won’t win them all.

University of Virginia professor Larry Sabato predicts up to an eight-seat gain for the House GOP, but others, including Rothenberg Political Report deputy editor Nathan Gonzales, say Republicans are more likely to gain between one and five seats, if any.

“There is somewhat of a limit to how many seats Republicans can gain, because they already control so many seats,” Gonzales noted.

Republicans currently hold the majority by a margin of 234-199.

Compare that to November 2010, when Democrats controlled Congress 255-179. The Rothenberg Political Report at the time listed 98 Democratic seats in play, many of them tilting Republican or pure toss-up.

The GOP had a far better opportunity to pick up dozens of new seats and did just that, gaining 63 seats in a landslide and taking the majority from the Democrats in the first midterm election of Obama’s presidency.

This year’s Senate races also limit how far the GOP can go.

There are 10 Democratic seats the Republicans have a solid chance of gaining, but polls in those races are very tight, in some cases dead even. Predictions range from a gain of four to eight seats for the Republicans. They need a net gain of six to win back the majority from Democrats, so the outcome is likely to be very close.

Indeed, there are some signs the public is hardly preparing to send a wave of Republicans to Congress in November.

Congressional approval ratings are abysmal, and the most recent generic ballot shows Democrats ahead by about one point. Other generic polls show Democrats leading by wider margins.

In contrast, just months before the GOP 2010 landslide, Fox News conducted a mid-August “generic” congressional poll showing the Republicans leading Democrats by 7 points. Fox conducted a similar poll two weeks ago, and this time, Democrats are ahead by 7 points.

And while Obama’s approval ratings hover in the low 40s, a Rasmussen Reports survey released this week found House Speaker John Boehner, R-Ohio, to be the most unpopular leader in Congress.

“The political environment is definitely better for Republicans because Democrats hold the White House,” said Jennifer Duffy, senior editor for the Cook Political Report, which rates congressional races. “But we don't see the kind of big wave developing, because voters are pretty unhappy with the Republican Party. They aren't thrilled with Democrats but seem to dislike them a little less.”

Gonzales said the most important polls are the ones used to measure individual races, and those point to a GOP victory in November.

“I think the Republicans are going to have a good election night,” Gonzales said. “It’s just a question of how good it is going to be."