Brynn Anderson, Associated Press
Republican presidential candidate Donald Trump speaks to supporters during a campaign rally, Saturday, March 5, 2016, in Orlando, Fla.

Four men remain in contention to be the next presidential nominee of the Republican Party. Last Thursday, 2012 standard-bearer Mitt Romney said that one of these men was not like the other.

Call it an unendorsement speech.

At least it also was a recognition that of the other three candidates — Sen. Ted Cruz, Gov. John Kasich and Sen. Marco Rubio — each has something of compelling case for their party's nomination. "One of these men should be our nominee," Romney said.

Romney's substantive and serious argument was "an extraordinary public rebuke" of the party's front-runner, said the New York Times.

Romney used logic and reason to emphasize the devastating costs that would follow from trade wars, and impulsive and rash foreign policy positions.

And he laid out the path that Republicans must take as they approach their July convention in Cleveland: "If we Republicans choose Donald Trump as our nominee, the prospects for a safe and prosperous future are greatly diminished."

He took on the issue of character: "Donald Trump says he admires Vladimir Putin, while he has called George W. Bush a liar. That is a twisted example of evil trumping good."

And he also asserted — defying convention wisdom — that Trump's nomination is not a foregone conclusion.

While political conventions have not generally been necessary to select presidential nominees over the past two generations, there's no reason why now isn’t the perfect time for a back-to-the-future moment in political parties.

For example, Abraham Lincoln arrived in Chicago at the Republican National Convention in 1860 as a distinct underdog to New York Senator William Seward and Ohio Senator Salmon Chase.

Lincoln, however, was more acceptable to a majority of the convention delegates. He was nominated on the third ballot. For nearly the next century, convention battles were frequent and numerous in both the Democratic and Republican Parties.

Romney's direct yet dignified attacks on Trump at the Hinckley Center at the University of Utah came at a time when some in the party are also seriously considering the need to mount a third party bid. Such a move would permit voters to choose someone other than Trump or presumptive Democratic Party nominee Hillary Clinton.

In a widely circulated public post on Facebook, Nebraska Sen. Ben Sasse said, "If Donald Trump becomes the Republican nominee, my expectation is that I will look for some third candidate — a conservative option, a Constitutionalist."

The irony is rich. Back in July, soon after Trump announced his candidacy, the Republican Party's priority was to entice commitments from nominees that they not run such a third-party campaign. At the time, Trump was seen as more of a threat outside the party than inside.

Oops.

However, Republicans being wrong eight months ago doesn't mean that Americans should be wrong eight months from now.

And Americans are waking to a nightmare scenario.

Put simply, the choice between Hillary Clinton and Donald Trump is nothing more than the choice between two left-leaning liberals, each of whom have strategically calculated and exploited a handful of populist positions that rouse their most zealous partisans.

Clinton leaned very far to the left because of her challenge from socialist Sen. Bernie Sanders. Now she has an almost-certain assurance that she will have enough delegates to secure the nomination.

I fully expect that on the all-important issues around the economy, Hillary Clinton would run to the right of Trump, were he were to receive the Republican nomination. All Hillary has to do is follow the example her “triangulating” husband, former President Clinton.

Unfortunately, no one expects that either Clinton or Trump would show reverence for our nation's founding document. And that possibility — the lack of a serious option for free-market constitutionalists — invites this thought: Is it too early to start planning now for the creation of a new political party, the Constitution Party?

The new party would embrace an originalist understanding of the Constitution, immigration, free trade, and emphasize the benefits that technology brings to the economy, to education and to the environment.

In recent decades, Republicans have traditionally been the home for (some) of these views, particularly with respect to the Constitution. But party realignments have taken place before in our history, and could take place again.

In many respects, the Whig Party of the 1820s-1850s was the forerunner of the Republican Party that was born to combat the expansion of slavery. The Whig Party's soft underbelly was its embrace of American Party, also known as the Know-Nothing Party. Its members strongly opposed immigration and Catholics.

If Trump were to be nominated, history might repeat itself. And the Party of Lincoln could, in a few years' time, end up as ill-fated as the Whig Party.

Drew Clark is of counsel at the law firm of Best Best and Krieger, where he focuses on technology, media and telecommunications. Connect on Twitter @drewclark or via email at drewclark@bbklaw.com.