You've heard the phrase before: "Where there's smoke, there's fire."

If I come home from the office today and my favorite vase is smashed to pieces, and my cat is crouched next to it with a guilty face … well, where there's smoke, there's fire.

Like my cat, both Hillary Clinton and Donald Trump are struggling with smoke/fire problems this election. They vehemently deny they did anything wrong in two separate issues plaguing their campaigns. But their opponents, and — in some cases — a majority of voters, think otherwise.

Let's run through both candidates' smoke plumes and how they could set fire to their campaigns:

1) Hillary Clinton's emails

Cue Hillary Clinton Blackberry photo. (Kevin Lamarque/AP)

What Clinton says: She did not knowingly send or receive classified email over the private server she used exclusively as secretary of state. And if she could have done things over, she wouldn't have used the private server.

Where her opponents see smoke: Well, a lot of places. Most recently, Monday, when the FBI released emails of a top State Department official asking the FBI to ease up on the rules for what information is classified. In exchange, the State Department would allow the FBI to go to countries where they weren't supposed to. (The FBI said this official was not involved in the investigation into Clinton's emails, and there's zero evidence the State Department official was acting on behest of Clinton or anyone in particular.)

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How it could turn into a fire: Fix Boss Chris Cillizza explains: "The idea of setting up a quid pro quo when it comes to classifications of information will, for many people, confirm their suspicions that the government bureaucracy is simply protecting Clinton. If a State Department official is offering a quid pro quo in this one exchange, can you imagine what they are doing off the books?"

I'll add that this plays into a perception that Clinton is dishonest. In September, Washington Post-ABC News asked voters whether they thought Clinton was honest and trustworthy; 60 percent said "No."

2) Donald Trump's accusers

(Sarah Rice/Getty Images)

What Trump says: He didn't inappropriately touch or sexually assault any of the nine women who have accused him of such. In fact, he suggested at a rally over the weekend, they're not attractive enough to warrant his attention in the first place.

Where his opponents see smoke: Actually, Clinton isn't saying much about this, preferring to let Trump flail on his own.

So let's rephrase to ask where VOTERS think there's smoke: A majority of likely voters think Trump made unwanted sexual advances toward women — 68 percent, according to a new Washington Post-ABC News poll. And 57 percent said they think Trump's apology for his 2005 "Access Hollywood" tape was insincere.