Why?  Hope and change, baby!  Eighteen months after Barack Obama took office on a promise to change business as usual in Washington DC, business is better than usual for the usual suspects.  A new poll by Politico shows that Beltway denizens are much happier with the state of the nation than those whom they supposedly serve, and for good reason:

America is struggling with a sputtering economy and high unemployment — but times are booming for Washington’s governing class.

The massive expansion of government under President Barack Obama has basically guaranteed a robust job market for policy professionals, regulators and contractors for years to come. The housing market, boosted by the large number of high-income earners in the area, many working in politics and government, is easily outpacing the markets in most of the country. And there are few signs of economic distress in hotels, restaurants or stores in the D.C. metro area.

As a result, there is a yawning gap between the American people and D.C.’s powerful when it comes to their economic reality — and their economic perceptions.

A new POLITICO poll, conducted by market research and consulting firm Penn Schoen Berland, underscores the big divide: Roughly 45 percent of “Washington elites” said the country and the economy are headed in the right direction, while roughly 25 percent of the general population said they felt that way.

Politico plans a six-month run of its Power and the People surveys, but if so, they’d better pay more attention to their sample.  The poll sample consists of 38% Democrats and 31% Republicans, with 22% claiming to be independent and the remaining 9% unclear on the concept.  The seven-point margin is the same size as the popular vote gap by which Obama won office, which is hardly a good indication of accuracy after almost two years of Tea Party organizing and serious damage to Obama’s support.  This sample overemphasizes Democratic input while shortchanging Republicans and especially independents.

Even with that advantage, Obama doesn’t do well at all in this poll.  Oh, he does very well with “DC elites,” to use Politico’s label, with a 66/34 rating.  Among the hoi polloi, though, Obama gets a 48/47 thanks to that skewed sample.  Among independents, he’s underwater at 42/47.

Interestingly, there is one thing on which both the country at large and DC elites agree: Congress stinks.  The general population gives Congress a 25/64, while Beltway insiders give it a 29/61 approval rating.  Actually, there are two things on which the two populations agree, the second of which is that neither likes Nancy Pelosi, either.  She gets a 23/52 in the general survey, with 25% saying that they don’t know enough to tell.  Pelosi gets a 45/52 in DC.

The skewed sampling should be kept in mind when looking at generic ballot questions, too.  The poll shows Democrats edging the GOP on the generic Congressional ballot 32/31, which basically means that the GOP holds its sample while Democrats lose close to 20% of theirs (38% to 32%).  Nine percent goes to an “Independent Party candidate,” which means an anti-incumbent vote.  The upshot here is that in a realistic sample with a two-way race, Republicans are leading.

Readers won’t need that much calculation for the presidential ballot.   Pitting Obama against a generic Republican in 2012 has him behind by five points, 42/37.  Among independents it’s a seven-point split, 33/26.  That changes when Politico names the GOP candidates; Obama wins every matchup with a named opponent, although he doesn’t get above 40 except with Sarah Palin, 48/36.

One last takeaway: like most other pollsters, Politico finds strong support for continued offshore drilling, 52/30.  Given the tilt of the sample, this makes clear again that bipartisan consensus exists for offshore drilling.