Cohen cites polls from New York Democratic primaries going back to 1989. One example, 1993, can probably be removed from the set, in which an incumbent mayor won re-election. The other five look like this — with 2013 included for comparison. The graph shows the percent of support the leading candidate received compared to the person in second place. In 2013, that leading candidate is City Council Speaker Christine Quinn. The runner-up is Weiner.
In each of the cases presented (except, of course, for 2013) the person who was leading in this average went on to win the Democratic nomination. (Only in 1989 did that candidate then win the mayorship.)
Two of the races deserve special attention — the two in which the leading candidate drew less than 30 percent support. In the first case, 2001, the two top candidates were forced into a run-off, after the leading candidate, Mark Green, failed to get 40 percent in a primary election that was delayed by the Sept. 11 attacks. He prevailed in the run-off, although barely. In the second case, 2009, the person drawing the most support decided not to run for mayor after all. That candidate, supported by nearly 32 percent of voters, was Rep. Anthony Weiner.
For Weiner to win this year, one of two things needs to happen. The first is that a poll or polls come out that bump his average into the lead. That's pretty unlikely. If Weiner polled at 60 percent support in a new poll, and Quinn at 10, Weiner would take a 30-to-29 lead in the average. But such a swing in support for Weiner would likely require some massive scandal to befall Quinn — these things happen — and necessitate that Weiner scoop up all of her lost supporters.
The other thing that could happen for Weiner to win is a less dramatic version of the same thing. Weiner needs to keep gaining support until the September primary. Between mid-April and late May, he , meaning that to make up the existing deficit at the current pace he only needs another three months.
Which would bring us to mid-September.