That’s what Chris Cillizza of the Washington Post says. His assessment is based on the way Iowa’s Democratic caucuses work.
The Democrats use a “viability threshold.” If a candidate doesn’t reach it at a particular caucus, his supporters are offered the opportunity to re-caucus on behalf of a candidate who is viable. (I don’t believe the Republicans use this procedure these days.)
O’Malley, who is at around 3 percent in the polls, is unlikely to reach the viability threshold at the vast majority of caucus sites. Cillizza speculates that, with the margins between Sanders and Clinton likely to be very close, O’Malley supporters might end up determining the outcome.
It happens that O’Malley’s level of support in the usually quite predictive final Des Moines Register poll — 3 percent — equals Hillary Clinton’s margin over Bernie Sanders in the same poll. But not all of O’Malley’s supporters see Sanders as their second choice; indeed, it’s not clear that most of them do.
It would take a very close race indeed for O’Malley supporters to decide it. Stranger things have happened, but to answer the question posed above, I don’t consider Martin O’Malley the most important person in the Democratic race.
For that honor, taking a broad view of “in,” I nominate James Comey or Loretta Lynch.