As vice president, Joe Biden has repeatedly delivered comic relief with verbal gaffes. But that doesn't mean his potential presidential candidacy is entirely a laughing matter.

After all, four of our last nine presidents first served as vice president.

Yes, former Secretary of State Hillary Clinton is the dominant early front-runner for the 2016 Democratic presidential nomination. Yes, Mr. Biden would be 74 on Inauguration Day 2017.

Yet the vice president keeps sending signals of his higher ambitions. On the opening edition of NBC's "Late Night with Seth Meyers" on Monday (it aired very early Tuesday morning), he told the host: "I had planned on making a major announcement tonight, but I decided tonight's your night. I hope you will invite me back."

Later Tuesday on ABC's "The View," Mr. Biden offered to reveal his 2016 decision if co-host Barbara Walters would change her mind about retiring. A few minutes after Ms. Walters declined that "deal," the vice president told the audience: "It's as likely I run as I don't run."

He added: "I think my knowledge of foreign policy, my engagement with world leaders, my experience uniquely positions me to follow through on the agenda Barack [Obama] and I have of bringing about world peace in a way that is real and substantive."

Certainly Mr. Biden has injected "real and substantive" humor, albeit usually unintentionally, into the too-often-sanctimonious tone of modern U.S. politics. A mere three examples from his VP spoken-blunder multitude:

While paying a 2010 St. Patrick's Day tribute to visiting Irish Prime Minister Brian Cowen at the White House, the vice president said: "His mom lived in Long Island for 10 years or so. God rest her soul. And - although, she's - wait, your mom's still, your mom's still alive. Your dad passed. God bless her soul."

Well, he meant well.

While on the 2012 campaign trail in Michigan, the vice president assured the crowd: "Folks, I can tell you I've known eight presidents - three of them intimately."

Fortunately, he didn't name names.

While on a gun-control push last year in New York, he pointed out that "Gabby Giffords, my good friend, was shot and mortally wounded."

Actually, the then-Arizona congresswoman was seriously - not mortally - wounded in 2011.

But hey, we all make mistakes.

And at least Mr. Biden, unlike Mrs. Clinton, never said this when asked about what went so horribly wrong before, during and after the Sept. 11, 2012, terrorist attack that killed four Americans in Benghazi, Libya:

"What difference at this point does it make?"