Public Policy Polling, a Democratic firm with a decent track record this year, has raised the question of whether an endorsement by President Obama will help or hurt Democratic candidates in a number of states.

The answer: ouch.

[I]t’s looking more and more clear that there’s just about nowhere Democratic candidates would benefit from having the President come to campaign with them.

In Illinois, Louisiana, Pennsylvania, Ohio, and Wisconsin an Obama endorsement comes down as a net negative impact on the chances of a voter supporting a candidate by anywhere from 14 to 33 points. There are two reasons for that. First, Republicans respond more negatively to Obama than Democrats do positively.

Second, independents are completely unimpressed by an Obama endorsement. In Ohio 6% say they’re more likely to support an Obama endorsed candidate while 57% say they’re less likely to. In Wisconsin it’s a 6/51 spread. In Pennsylvania it’s 10/56. In Illinois it’s 15/39 and in Louisiana it’s 16/49.

We’re always hearing about how the Tea Partiers and conservative candidates are supposedly going to alienate independent voters, but we haven’t seen that  happen yet. The real story seems to be that President Obama is alienating them already, and by a pretty wide margin.