Joe Biden isn’t running for president. He’s running for the U.S. Senate.

At least, that’s what he told South Carolina voters during the state Democratic Party’s First in the South Dinner Monday night.

"You're the ones who sent Barack Obama the presidency. And I have a simple proposition here: I'm here to ask you for your help," Biden asked of the audience. "Where I come from, you don't get far unless you ask. My name's Joe Biden. I'm a Democratic candidate for the United States Senate. Look me over. If you like what you see, help out. If not, vote for the other [guy]. Give me a look, though, OK?"

Biden is well-known for his verbal blunders, and although they’re often embarrassing — he once misidentified New Hampshire as Vermont when speaking to a group of New Hampshire voters and referred to Barack Obama as "Barack America" — they’re not necessarily disqualifying. Should Biden, who often touts his work with the civil rights movement, know the decade in which Martin Luther King Jr. was assassinated? Probably. Will his warped internal calendar make him a bad president? Probably not.

The problem, however, is that voters are starting to ask questions about Biden’s mental acuity and whether he can do the job if he’s elected. These questions are fair. Biden is old, and although his neurologist assured voters that the 77-year-old former vice president is just “as sharp as he was 31 years ago,” he’s still blundering his way across the campaign trail.

Biden deserves some grace. Unlike some of the other Democratic candidates, his biggest verbal mistakes have been accidents (except for that one time he referred to a female voter as a “lying, dog-faced pony soldier,” which was supposed to be a joke — she didn’t take it that way). Michael Bloomberg, on the other hand, admitted on the debate stage last week that he habitually made distasteful jokes about women that resulted in nondisclosure agreements. And Bernie Sanders is still defending communist dictator Fidel Castro.

Then, there’s Biden, whose worst rhetorical fault as of late is mixing up which political office he’s trying to win.

Still, we shouldn’t underestimate the effect Biden’s slip-ups could have on what is already a sinking presidential campaign. Biden’s presidential bid has always relied on two things: nostalgia for the Obama era and Biden’s electability. Right now, those two selling points are being overshadowed by Biden’s lack of energy and his campaign’s lack of political momentum.

But don't worry. As Biden assured voters last year, “I want to be clear," he said. "I’m not going nuts.”