In anticipation of the Pennsylvania primary tomorrow, both the Clinton and Obama campaigns are furiously trying to set expectations. But the election is not taking place in a hothouse of spin -- it's taking place in the real world, where no one number will tell the whole story.
1. A win is a win. The Clinton campaign argues that winning is the only thing that counts. That's true to the extent that, for her, losing would effectively end the race (which is not to say that Hillary herself would give up). But other than avoiding a death knell, a mere one-point win is a pretty low bar for a candidate who led by double digits in every poll this year until March 30.
2. Polls. Eight of the ten final polls show Hillary winning by margins of 5 to 10 points. That range is probably the benchmark for actual expectations -- bigger will be treated as a Hillary surprise, smaller as an Obama surprise.
3. A more meaningful benchmark may come from Ohio. In Ohio, a neighboring state, Hillary beat Obama 54-44 -- by ten points. Pennsylvania (see chart, via Atlantic) is older than Ohio, with more Hispanic voters and fewer black voters. In all three respects, the state is more favorable to Hillary. Voters are also, however, slightly better educated -- which favors Obama.
The Clinton campaign contends that the bar has to be set higher for Obama because he has outspent her by a margin of between 2-1 and 3-1 in Pennsylvania. On the other hand, Obama has taken big hits on the Jeremiah Wright and "Bittergate" controversies since Ohio. If he only cuts the margin to 9 it will be hard to portray that as a success, but if the margin is 5 or 6 in a state with more of the white, working class voters that should have been most offended, he'll have an argument.
4. Delegates. Clinton trails Obama by 166 pledged delegates and 800,000 in the popular vote, excluding Florida and Michigan per party rules. Her best hope by June is to significantly tighten the delegate margin and try to overtake Obama in the popular vote, but the first step toward doing that is winning Pennsylvania -- the largest remaining state -- by a margin of more than 20 points, or 60-40.
If Obama loses by, say, 15, it will be hard to spin it as a win. But the day after, he may well argue that Hillary fell short of what she needed to have a shot at winning the nomination -- and, in that sense, lost.
5. Superdelegates. If she can't catch up in the popular vote or pledged delegates, the Clinton campaign hopes superdelegates will nonetheless swing the nomination to her based on an argument that Obama's lack of support among the party's white, working class base would be fatal to his electability.
That argument will be tested by the exit polls as much as the final outcome. Obama lost white Catholics 65-35 and people earning less than $50,000 by 56-42 in Ohio. If he doesn't improve on numbers like that, Hillary's argument will get stronger. If he does, it will erode.