Third-Party Challenge Faces Long but Not Impossible Odds

— -- The contentious primary season may be winding down, but third-party activists are still mulling the possibility of launching an eleventh-hour alternative to a likely Donald Trump-Hillary Clinton matchup in November.

With the first major independent ballot deadline coming on Monday in Texas, potential third-party backers face an ambitious but not insurmountable calendar of ballot access requirements that call for tens of thousands of signatures.

“I would say it’s very feasible,” ballot access expert Richard Winger told ABC News. “The vast majority of deadlines are in July, August, and September, and even for those that are earlier, they are probably unconstitutional and can be overturned in court.”

The discussions come as top elected Republicans split over whether to back their presumptive nominee, Trump. The most prominent defection so far has been House Speaker Paul Ryan, the highest-ranking elected GOP official in the country, who said yesterday he was not ready to back Trump yet.

One group, Conservatives Against Trump, is seeking out a potential third-party candidate to run, talking behind the scenes with potential hopefuls like Nebraska Sen. Ben Sasse and Mitt Romney.

"We will begin now laying the groundwork for an exit strategy from Donald Trump's Republican Party,” said Bill Kristol, editor of the conservative magazine The Weekly Standard and a prominent supporter of a third-party option.

Sasse says he is not interested in running, but bemoaned the two likely candidates and called for a third option.

One strategy under discussion has been the co-opting of a minor political party as a vehicle to challenge the Republican and Democratic nominees this November. But the prospect of infiltrating these parties from the outside faces long odds.

Among the minor parties, the Libertarian Party has gained perhaps the most attention as the only third party with a realistic shot at appearing on the ballots of all 50 states plus the District of Columbia. As of this week, the party had qualified for 32 state ballots ahead of its May 27-30 convention, where it will chose presidential and vice presidential nominees.

Once selected, the Libertarian nominee is locked in and cannot be changed before the election, meaning anti-Trump forces would need to act quickly before this month’s Orlando, Florida, convention if they hope to remake the party in their likeness.

A high-ranking Libertarian Party official told ABC News that while it’s possible an independent could get on the ballot at the convention, a successful last-minute candidacy is extremely unlikely.

“At this point, convincing a very decentralized set of delegates from around the country to vote for them on first ballot, or any ballot, would take a very significant effort, coupled with name recognition, coupled with demonstrating Libertarian positions,” the official said. “A newcomer would have be awfully darn good at this point. It’s very difficult to jump in this late.”

In recent weeks, prominent anti-Trump advocate Kristol also floated the idea of using the Reform Party as a vehicle for stopping Trump and Clinton.

“There is also the possibility of getting on the ballot of a small party that’s already on the ballot in North Carolina and Texas. The Reform party in particular,” he said during an April 26 appearance on MSNBC. “I think it is more doable than people think.”

But two Reform Party officials told ABC News the party doesn’t anticipate having a viable presidential candidate this year, as it only expects to appear on a total of four or five state ballots.

The Constitution Party, which holds similar views as the Libertarian Party, is currently on 18 state ballots and hopes to be on 46 by November. But unfortunately for anti-Trump activists, the Constitution Party locked in its nominee last month.

“Quite a number of Never Trump people contacted us,” said Joan Castle, the wife and campaign manager of Constitution Party nominee Darrell Castle. She said that some of the Never Trump advocates have rallied around her husband, adding: “We can win if people don’t hide behind their fear of not being on the winning team.”

Asked this week what recourse there is if no adequate alternative to Trump or Clinton emerges before voting time, Kristol told CNN: “I will write in someone appropriate.”