The electoral wave threatening congressional Democrats this fall looks at least as big as the breakers that flattened congressional Republicans in 2006 and 2008. But the odds are high that this won't be the last storm surge from an angry sea of American discontent.

Democrats are facing a midterm drenching partly because they have inspired an ideological backlash among small-government voters. But their greatest problem is that they control all of Washington's levers at a time when most Americans are deeply unhappy with the country's direction. Even as voters prepare to send more Republicans to Washington, polls show that Americans are not enthusiastic about the GOP. Indeed, the arc of disillusionment spreads beyond the two parties to virtually every major American institution. If November's election allowed Americans the opportunity to fire not only members of Congress, but also the nation's entire public and private leadership class, they might take it.

This deep, broad, and visceral discontent is a recipe for social and political volatility. As recently as 2004, GOP strategists such as Karl Rove saw in George W. Bush's slim re-election evidence that Republicans were building a "narrow but stable" electoral majority. That was immediately followed by Democratic routs in 2006 and 2008 that reduced the GOP to virtually a rump Southern party and inspired Democrats to dream of their own lasting majority. Two years later, Democrats are struggling to hold even one chamber of Congress.

The severity of these swings testifies to the distance separating many voters from either party. When asked to rate the performance of congressional leaders in a SHRM/National Journal Congressional Connection poll last month, only about one-third of adults gave positive marks to either Republicans or Democrats. Strikingly, nearly three-tenths said they disapproved of the job performance of both Republican and Democratic leaders. That number rose to 41 percent among independents.

In that survey, conducted by the Pew Research Center, nearly half of independents gave both Republican and Democratic leaders poor marks on placing the national interest ahead of their own political interests. Similarly, in a recent Washington Post/ABC News poll, a comparable 43 percent of independents (and 36 percent of all voters) said they lacked confidence that President Obama, congressional Republicans, or congressional Democrats can make the right decisions for the country's future. All of these findings represent a striking no-confidence vote in the nation's political class.

And the alienation hardly stops there. In a July Gallup survey, a majority of Americans expressed confidence in only three of 16 major institutions tested: the military, small business, and the police. Newspapers, banks, television news, organized labor, big business, health insurers, and Congress all drew positive marks from one-fourth or less of those polled. Even organized religion, the medical system, and the U.S. Supreme Court failed to inspire confidence in a majority of Americans.

One final trend underscores these findings. On virtually every measure discussed above, whites, still by far the largest group in American society, expressed even more alienation than minorities, even though minorities, by all measures, have suffered more from the lengthy economic downturn. Nothing captures this pessimism gap more than the fact that whites, in several surveys this year, have been more likely than minorities to say that they did not expect their children to match their own standard of living.

If polls existed just before the French Revolution, they might have returned results such as these. They point toward a widely shared conviction that the country's public and private leadership is protecting its own interest at the expense of average (and even comfortable) Americans. The lasting downturn has deepened those sentiments, but it didn't create them and its end probably won't dissolve them. Americans increasingly believe they are paddling alone on a treacherous economic sea -- which helps explain why they so enthusiastically submerge those in charge whenever they get the chance.

That instinct suggests neither side should fully unpack when it wins power in Washington; its lease could be short-term. It also increases the odds of a crowded stage in the 2012 presidential campaign. Although the practical barriers to a third-party candidate remain substantial, these findings document a substantial audience that might consider a non-politician with a problem-solver pedigree, especially if the economy remains weak. Above all, this collapse in confidence is making it more difficult to maintain majority support for any governing direction, even as the nation's need grows for sustained responses to its mounting docket of challenges.

rbrownstein@nationaljournal.com