Trump vs. Bloomberg: Who's a better third-party candidate?

A feud with Ted Cruz has Donald Trump again threatening to launch a third party run.

This time, he's got competition. Former New York Mayor Michael Bloomberg recently confirmed that he is considering entering the 2016 presidential race as a third-party candidate.

That means two loudmouthed New York billionaires, both of whom have flip-flopped between the Democratic and Republican parties, are threatening to upend the 2016 race by launching independent bids for the White House.

Who's a better third-party candidate? The better question is whose third-party candidacy would hurt which party the most?, says David McLennan, visiting professor of political science at Meredith College in Raleigh, N.C.

"Donald Trump would be far more effective as a third-party candidate because his base of support is clearly defined and passionate about his candidacy," he says. "Michael Bloomberg doesn't have a natural base of support that is unique like Trump's. ... He is less bombastic than Trump, which in an election year like this one may mean he gets little attention."

Mr. Bloomberg, known for his socially liberal stance on issues such as gun control, abortion, and public health policing, would appeal to liberal voters and almost certainly siphon votes from the Democratic nominee.

In hypothetical head-to-head match-up between Trump and Hillary Clinton, for example, Mrs. Clinton narrowly leads Mr. Trump 44-to-42, according to a Jan. 2016 poll. Introduce Bloomberg to the equation and Clinton loses to Trump, 37-to-36. With Bloomberg in the race, Clinton’s support would decline the most among independents (36 to 24 percent) and adults under 30 years old (52 to 41 percent).

That said, Bloomberg wouldn't make a great third party candidate. He's 74, largely unknown nationally, and has been described as uncharismatic. In fact, the former Big Apple mayor has himself expressed doubts about the electability of a "short, Jewish, divorced billionaire."

Of course, being a twice-divorced billionaire with a loud mouth, a penchant for insults, and high unfavorable ratings hasn't stopped Trump from running – and so far, mostly winning.

That's because, as a strategist, he's been brilliant. Trump, who has been threatening to run for years, has impeccable timing. He chose to run when there's no incumbent president; when the GOP side has a large, hotly contested field; and when the presumptive Democratic nominee is loathed by a large segment of Americans.

And he's re-written the rules and upended the Republican race with his outrageous style.

As one outlet put it, "Trump shows up to a debate and it’s a big story. Trump refuses to show up to a debate, and it’s an even bigger story."

Which is why forecasting blog FiveThirtyEight says Trump "might be the closest thing we’ve seen to a viable third-party candidate in a long time."

Should he launch a third-party bid, Republicans have good reason to be concerned.

In hypothetical general election match-ups, Clinton would lose to both GOP candidates Ted Cruz and Marco Rubio. She would lose to Cruz by 3 points, 47 to 44, and to Rubio by 7 points, 48 to 41, according to a December Public Policy Polling survey.

Introduce Trump, however, and Clinton wins, with Trump taking a significant percentage of votes from his GOP rivals. In a three-way contest between Clinton, Sen. Rubio, and Trump, for example, Trump would take 23 percent of the total votes, and Clinton would best Rubio 39-to-33.

Similarly, the billionaire businessman would earn 20 percent of the vote in a three-way contest with Clinton and Sen. Cruz, giving the former secretary of state an 8-point lead over the Texas senator.

"If Donald Trump doesn't stick to his pledge not to run as an independent it could pretty much doom the Republican Party next fall," said Dean Debnam, president of Public Policy Polling, in a statement.

Of course, all these hypotheticals and what-ifs are probably for naught.

"Third-party candidates are rare, and for good reason," reports the Christian Science Monitor. "It is difficult to win an election in a two party system without the backing of an organization like the Democratic or Republican parties. The electoral college, which awards state electors to candidates on a (generally) winner take all basis, can also prevent even popular third-party candidates from defeating those backed by a party machine."

Which is why there hasn't been a single successful third-party presidential candidate in modern American history, points out the American Prospect's Paul Waldman for the Washington Post.

"It ain’t gonna happen," he proclaimed last month. "Not only is Bloomberg not going to run, but if Trump wins the Republican nomination, every last prominent Republican will line up behind him like good soldiers."

Third-party run or not, he adds, "Don’t worry — it’s still going to be an interesting election."