Donald Trump, should he decide to run on a third-party ticket, may have as profound an impact on the presidential election as the Bull Moose, Teddy Roosevelt, in 1912.

The prospect of a more-than-two-party presidential election holds a fascination for Americans, probably because such a race is so rare these days. And for the leadership of the national political parties? Their fascination reaches quivering obsession.

Why? Because an outsider’s influence can be calamitous.

Let’s look at the presidential election in 1912. It was a four-way race.

Toward the end of his second term, progressive Theodore Roosevelt groomed William Howard Taft to be his Republican successor. Teddy believed Taft shared his zeal for progressive reform.

Taft easily won the Republican nomination, and easily won the 1908 election. But he took a far more conservative approach to Teddy’s progressive agenda.

Teddy had busted up the “trusts” of big railroads and big oil. He had lent his political support to labor unions. He had created federal departments to regulate food and drug safety. He had increased taxes on the wealthy. He had purchased private lands to be nationalized into wilderness sanctuaries accessible to all Americans, not just the privileged few.

Yes, believe it or not, Teddy was a Republican.

But Taft, after his inauguration, set out on a more conservative course, relying upon judges to settle what is fair and equitable, rather than relying on government and politicians.

Teddy felt he had been betrayed.

Instead of supporting fellow Republican Taft’s nomination for a second term, Teddy, claiming he was strong as a “bull moose,” accepted the nomination of the Progressive Party. Democrats nominated the governor of New Jersey and former president of Princeton University, Woodrow Wilson. And there was a serious fourth-party contender, Eugene V. Debs. A reader of Karl Marx and a founder of the Industrial Workers of the World (IWW), Debs, in the 1908 presidential election, historian Scott Berg notes, had won three percent of the vote as the Socialist Party for America candidate.

Hear a loud bang? Probably the fuses at FOX News exploding.

So. Let’s have some fun.

Let’s pretend the presidential election of 2016 is a four-way race between Jeb Bush for the Republican Party, Donald Trump for the (what else?) Trump Party, Bernie Sanders for the Socialist Party, and Hillary Clinton for the Democratic Party.

Oh, the 1912 race? It came down to the blustery Roosevelt vs. the cerebral Wilson, the first Democrat to take up residence in the White House after more than 40 years.

You make the call.