In a sad way, the strategy makes sense.

With a variety of methodologies, polls suggest that the percentage of undecided voters is in the neighborhood of 25 percent. A recent survey by USA Today/Suffolk University identified nearly one in five respondents holding a negative view of both Clinton and Trump. When asked to choose between the two, 26 percent chose Trump, 19 percent chose Clinton, and 44 percent were undecided.

Although Trump has a slight edge, said David Paleologos, director of the Suffolk University Political Research Center, “the majority are up for grabs as these voters grapple with holding their noses and picking one of them or opting for a third party option. Or staying home, come November."

The dynamic exists in each state. In Michigan, 32 percent of voters called themselves undecided in a poll by the Lansing-based Marketing Resource Group, roughly the share of the vote going to both Clinton and Trump.

The high number can be partly attributed to the firm's decision not to ask which way voters leaned if they were uncomfortable committing firmly. Still, it’s twice the number of uncommitted Michigan voters the firm identified at this point in the 2012 presidential cycle.

“Trump and Clinton are trying to disqualify each other,” said Chris Kofinis of Park Street Strategies, a public relations and research firm based in Washington.

It is delicate work, considering the fact that undecided voters are united mostly by their intense frustration with the political system. Among their numbers are moderate Republican women, mostly white and suburban voters; young liberals who supported Bernie Sanders; and self-identified independents.

Trump can use Clinton’s record of scandal and deception to drive up her negative ratings among moderate women, but if he goes too far, those same voters might turn against him. “Threatening to jail your opponent is mean, and these people don’t like mean,” said the GOP consultant Alex Castellanos.

Accusing Clinton of murder, comparing her to the devil, and dredging up the Monica Lewinsky scandal represents the type and tone of politics that has pushed these voters out of the two major parties and into the “undecided” category. Yet Trump and his surrogates can’t seem to help themselves.

On the Benghazi and email scandals, for instance, there is a credible case to be made against Clinton’s management and honesty. Al Baldasaro didn’t make it. Instead, the New Hampshire state representative and Trump adviser on veterans issues said Wednesday, “The whole thing disgusts me. Hillary Clinton should be put in the firing line and shot for treason.”

Clinton faces a similar challenge. Her strategy depends on persuading Americans to vote against Trump because he is temperamentally ill-suited for the job, a liar and a bully who enriched himself by gaming the legal system and taking advantage of other people.