Is It Too Late for Another Candidate?

Two months ago I suggested that it might not be too late for another presidential candidate to enter the race. And I cited some ancient history:

Barry Goldwater announced his candidacy for president on January 3, 1964, about nine weeks before the New Hampshire primary. A decade later, Ronald Reagan announced his challenge to President Gerald Ford on November 20, 1975. After that unsuccessful race, he announced another, this time successful candidacy, on November 13, 1979.

Now the William J. Clinton Presidential Center (whatever happened to good ol' Bill? I guess "William J. Clinton" sounds more presidential) reminds us of a more recent president who started his campaign later than any of today's contenders. From September 30 to October 3, the center will celebrate the 20th anniversary of Bill Clinton's announcement of his candidacy, which happened on October 2, 1991.

Is time running out? Or could a candidate with something attractive to offer still get into the race? It's still earlier in the season than when Ronald Reagan and Bill Clinton announced their candidacies.