By now, candidates surely must know that everything they say will be instantly analyzed, dissected and, most importantly, fact-checked to make sure they are not fibbing. Outfits like PolitiFact and FactCheck make their living by exposing politicians who are challenged by the truth.

So I can’t understand why any serious candidate would risk the wrath of the truth-sayers and allow themselves to labeled as liars. Consider Democratic U.S. Senate candidate Patrick Murphy, for instance.

For context, consider that the latest Quinnipiac poll has Murphy virtually tied with Marco Rubio in the Senate race, assuming both win their Aug. 30 primaries and square off against each other in November. Murphy trailed 48-45 percent, within the poll’s margin of error.

That’s a 10-point pickup for Murphy in the Q-poll since July, likely helped in no small measure by a barrage of TV ads from President Barack Obama on his behalf.

But right away, Murphy gave an opening to those who say he can’t handle the truth. In an almost offhanded comment during an interview on Fusion TV, he declared, “I am an immigrant.”

No. He is not.

Unless Florida seceded from the Union in the last few years (I think we would have heard about that), Patrick Murphy is a Floridian. He was born here.

For context, the question posed to Murphy was about Donald Trump’s divisive comments regarding immigration. The young, would-be senator mentioned the Statue of Liberty, and concluded that answer by adding, “We’re all basically immigrants.”

I guess he was trying to make a point that the United States is a melting pot. So just say that. I mean, I have family roots that trace to Ireland, but that doesn’t make me an Irish immigrant. I was born in Dayton, Ohio — Go Buckeyes!

Anyway, after Murphy made that immigrant remark duty demanded that reporters and snarky columnists revisit other issues where his truthfulness has been examined. In June, a TV report in Miami questioned his experience and credentials as a CPA, or whether he actually owned a small business company involved in the cleanup of the Gulf oil spill.

Murphy’s campaign quickly put out a seven-page, point-by-point rebuttal to that story, calling it “deeply false” while also noting an instance where “material was corrected overnight, but that will surely appear in Republican attack ads.”

There you have it, citizens.

Politics is a contact sport, especially at this level. You don’t have to be an experienced politician to be attacked (see Carson, Ben). Opponents will seize on every statement that is open to interpretation and twists it to make you look like a serial liar.

It is the wise candidate who doesn’t give them that opportunity. That candidate realizes that in this world of 140-character instant judgment, the smallest opening can quickly become a chasm.

One explanation for Murphy’s rapid rise in the polls is the fact that Trump is a drag on down-ballot candidates because of his strained relationship with the truth. Couple that with the legitimate questions about Rubio’s performance during his first term as a senator and Murphy has a great chance to win in November.

However, as long as the headlines point out an unforced gaffe like his “immigrant” remark, that chance could become diminished in a most unnecessary way.