THOSE HELPFUL POLLS:

Continuing to prove that nobody knows who is going to win the Democratic nomination, the latest University of New Hampshire-administered poll (PDF) contradicts a poll the survey center took just four days earlier. Over the last two weeks, Obama’s support has gone from 30 percent to 26 percent to 30 percent, while Clinton’s has ranged from 31 percent to 38 percent to 28 percent. Obama and Clinton are now statistically tied, as if it matters.

The last few elections, the polls haven’t proved especially reliable.