The big news out of the Politico Battleground poll released Monday morning is that former Massachusetts governor Mitt Romney leads President Obama among independent voters by double digits. (the actual number is 48 percent to 38 percent.)

But, Obama’s troubles with independents are really nothing new. In fact, in polling conducted by the Washington Post-ABC News, Obama’s job approval rating among independents has been over 50 percent just one time in the last two years — and that was in the immediate aftermath of the death of Osama bin Laden last spring.

Read that again: The incumbent president’s job approval rating among the most electorally critical voting bloc in the country this fall has been better than 50 percent once in the last two years.

Here’s the trendline on those Post-ABC polling numbers:

It’s not all bad news for President Obama among independents, however. While he is in the midst of a sustained period of unpopularity with unaffiliated voters, Obama’s numbers are still better at this point that Romney’s.

In a mid-April Post-ABC survey, just 34 percent of independents had a favorable view of Romney while 47 percent saw him in an unfavorable light.

What all these numbers mean is simple: Obama almost certainly can’t win the votes of these independents with a positive message unless, of course, the economy gets measurably better — and soon.

Instead, the incumbent has to turn this election into a devil you know/devil you don’t know dynamic for independents. In essence: “You may not like me but you would like Romney even less.”

Brace yourself. This election is going to get nasty (or nastier) fast.