Can someone be a candidate for President or Vice President for more than one Party?

[NewYorkExpress]

So, let's say in 2000, Al Gore and John McCain win their parties respective nominations, and both pick Joe Lieberman as their running mate.

Would this be legal?

[brucejoel99]

Yes, there's nothing constitutionally or legally stopping competing elector slates from being pledged to support the same candidate.

[True Federalist (진정한 연방 주의자)]

In the 1824 election, there were enough Jackson/Calhoun, Adams/Calhoun, Crawford/Calhoun, and Clay/Calhoun electors that unlike the Presidential election which went into the House, Calhoun won the Vice Presidency outright without the Senate having to choose. The primary difficulty is that most States don't allow for electoral fusion, so that in a theoretical three-party race in which the PV in a State went:

Party One: Candidate P / Candidate V : 35%
Party Two: Candidate P / Candidate V : 20%
Party Three: Candidate Q  / Candidate W : 45%

Candidate Q / Candidate W would win, even if Parties One and Two had nominated the same slate of electors.

[An American Tail: Fubart Goes West]

In the 1824 election, there were enough Jackson/Calhoun, Adams/Calhoun, Crawford/Calhoun, and Clay/Calhoun electors that unlike the Presidential election which went into the House, Calhoun won the Vice Presidency outright without the Senate having to choose. The primary difficulty is that most States don't allow for electoral fusion, so that in a theoretical three-party race in which the PV in a State went:

Party One: Candidate P / Candidate V : 35%
Party Two: Candidate P / Candidate V : 20%
Party Three: Candidate Q  / Candidate W : 45%

Candidate Q / Candidate W would win, even if Parties One and Two had nominated the same slate of electors.

On the flip side, New York allows for fusion of electoral slates and this usually happens for the major party candidates. It didn’t happen for Gary Johnson in 2016 though; there were separate slates from both the Libertarian Party and the Independence Party.