We already knew that if the 2010 election had been held last Tuesday, lots of Democrats would have been in real trouble. The good news? We can be absolutely certain that the 2010 elections won’t be held until, well, 2010 — and that by then the environment is likely to be meaningfully altered.

{mosads}We knew these elections were not a referendum on President Barack Obama. With an approval rating of 57 percent in New Jersey’s exit poll, the president ran 12 points ahead of Gov. Jon Corzine (D). In Virginia, Obama’s approval rating was seven points higher than Creigh Deeds’s (D) vote total.

We knew that while exceptional performance among independents fueled Democratic victories in ’06 and ’08, neither party should count on their permanent allegiance. That’s why they call them independents! Both Chris Christie (R) and Bob McDonnell (R) won independents by vast, 2-to-1, margins.

As anticipated, the bleak economy motivated many defections, though the exit poll data appear ambiguous. In both New Jersey and Virginia, Republicans won those who reported being “very concerned” about the economy, but the Democrats won those who were “somewhat concerned.” In New Jersey, however, Corzine won voters who identified the economy as their most important issue by a 22-point margin. In Virginia, McDonnell won “economy” voters.

Everyone should have known that turnout would not match that of the presidential year. Off-off-year turnout never has and never will. While that comparison can be entertaining, it is not terribly meaningful. Yet some analysts, for reasons known only to themselves, insist on comparing this year’s turnout to 2008 instead of to the comparable year — 2005.

The data undercut the torrent of pre-election conventional wisdom forecasting that turnout would be decisive.

Heavily Democratic Essex County, N.J., recorded just about 3,000 fewer voters in 2009 than in 2005. The important difference? In 2005, Corzine won the county by 47 percentage points; in 2009, the margin was a lesser 39 points. In Middlesex County, about 6,000 more people voted in 2009 than in 2005. That might have accrued to Corzine’s benefit, had he won the county by the same 17-point margin he posted in 2005.

Instead, he lost Middlesex by two points.

If the exit polls are to be believed (and on turnout they should be taken with many grains of salt), President Obama did a relatively better job rallying the African-American community for Jon Corzine in 2009 than he did for himself in 2008 — African-Americans constituted a greater share of the New Jersey electorate this November than last.

Turnout was not the culprit in Virginia, either. In Alexandria, turnout was down by fewer than 1,000 voters, compared to 2005. Gov. Tim Kaine (D) won it by 50 points then; Creigh Deeds by far less — 32 points — this year. Arlington witnessed an uptick in participation, but the percentage of the vote won by the Democrat plunged.

In short, these Democrats lost not because they failed to turn out voters, but rather because they had too few voters to turn out.

What new lesson emerged from Tuesday’s results? The likes of Glenn Beck, Rush Limbaugh and Sarah Palin are poison for the GOP. Their meddling elected the first Democrat from the area of New York’s 23rd district in 150 years, on a night on which the odds were stacked against Democrats. Though these divisive figures are driving Republicans to ruin, few GOP candidates will have the courage to stand up to them, knowing their power in the party. Internecine warfare among Republicans is bound to escalate as both sides feel vindicated by the New York outcome.

Here’s to many more Republicans clashing.

Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982. Current clients include the majority leaders of both the House and Senate.