The politicians responsible for the resignation of Richard Nixon in August 1974 weren’t from the Democratic Party. The ones who succeeded in removing Nixon were, like him, Republicans. This is a group of Republican senators who had just finished meeting with Nixon and had urged him to resign. Nixon complied.

I offer this in light of the 2016 presidential campaign. Hillary Clinton’s most immediate threat isn’t Donald Trump. It’s really not even Republican leaders. More accurately, the source of her greatest threat is the Democratic Party. If Clinton’s poll numbers continue to decline relative to Trump’s, I suggest to you that we will suddenly see a new urgency in the upper echelons of the Democratic Party to review Clinton’s email controversy. The signals that President Barack Obama has sent–stating that she did nothing wrong–will be rewired to send off a different message. The recent findings of the State Department released on May 25, which are quite critical of Clinton, will be seen as the first step to a Democratic Party revision of Clinton’s conduct and its meaning for her candidacy. Any subsequent action by the FBI that adds to or elaborates on the negative outcomes of the State Department’s report will only intensify the velocity of this trend.

Watch Clinton’s poll numbers. And then watch for reactions from leaders of the Democratic Party. This is the combination that holds the greatest threat to Clinton’s candidacy.