Washington(CNN) Current Republican presidential hopeful Donald Trump won't rule out running as a third-party candidate for president should he fail to secure the Republican nomination -- but he'll have to beat obstacles in every state, including some "sore loser" laws.
Still, it's not impossible. In 1980, John Anderson pulled out of the Republican primary and ran unsuccessfully as an independent, appearing on all 50 states' ballots. In 1992, Ross Perot mounted a third-party bid that had him on all 50 states' ballots. In 2012, Gary Johnson began as a Republican candidate, but ended up running as a Libertarian -- making the ballot in 48 states and the District of Columbia.
RELATED: CNN/ORC poll finds Trump on top in Iowa
Trump will have to keep an eye on the calendar and make some strategic decisions on where he chooses to run if he wants to mount a third-party bid, said minor party activist and ballot access expert Richard Winger.
Winger, a Libertarian, has spent 40 years advocating for minor party candidates and maintains a website about ballot access.
To appear on ballots in all 50 states and the District of Columbia would require collecting about 570,000 signatures, he said.
According to a chart published in the July issue of his newsletter, the earliest deadline Trump would have to meet would be May 9 to get on the ballot in Texas. But Winger said a candidate could feasibly mount a legal challenge to that date, because Texas doesn't require independents for other offices besides president to file until June.
Who's running for president?
Ted Cruz, Donald Trump, John Kasich, Hillary Clinton and Bernie Sanders,
Businessman Donald Trump
announced June 16 at his Trump Tower in New York City that he is seeking the Republican presidential nomination. This ends more than two decades of flirting with the idea of running for the White House.
"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," Trump told the crowd at his announcement.
Sen. Ted Cruz of Texas has made a name for himself in the Senate, solidifying his brand as a conservative firebrand willing to take on the GOP's establishment. He
announced he was seeking the Republican presidential nomination in a speech on March 23.
"These are all of our stories," Cruz told the audience at Liberty University in Virginia. "These are who we are as Americans. And yet for so many Americans, the promise of America seems more and more distant."
Ohio Gov. John Kasich joined the Republican field July 21 as he formally announced his White House bid.
"I am here to ask you for your prayers, for your support ... because I have decided to run for president of the United States," Kasich told his kickoff rally at the Ohio State University.
Hillary Clinton
launched her presidential bid on April 12 through a video message on social media. The former first lady, senator and secretary of state is considered the front-runner among possible Democratic candidates.
"Everyday Americans need a champion, and I want to be that champion -- so you can do more than just get by -- you can get ahead. And stay ahead," she said in her announcement video. "Because when families are strong, America is strong. So I'm hitting the road to earn your vote, because it's your time. And I hope you'll join me on this journey."
Sen. Bernie Sanders, an independent from Vermont who caucuses with Democrats, announced his run in an email to supporters on April 30. He has said the United States needs a "political revolution" of working-class Americans to take back control of the government from billionaires.
"This great nation and its government belong to all of the people and not to a handful of billionaires, their super PACs and their lobbyists," Sanders said at a rally in Vermont on May 26.
Some other states also ostensibly have earlier deadlines, but those are being challenged in court, and previous Supreme Court decisions have supported that independent presidential filing deadlines should be summer at the earliest.
Other than Texas, four states have deadlines in June, and the rest are in July, August and September.
What may be more of an issue, though, are so-called sore loser laws, which essentially prohibit candidates from running in a party primary and then a general election as a candidate not from that party.
According to a 2011 Georgetown Law Review article by Emory associate law professor Michael Kang, all but three states have such laws on the books -- though Kang's research was focused more on congressional elections, he told CNN in an email.
"The laws for presidential elections are sometimes different and I think always in the less restrictive direction," Kang said. "Even some states with outright prohibitions on sore loser candidates for Congress or other offices have an exemption for presidential candidates. So applied to Trump's case, there's a lot less in the way of an independent run for a president than there would be for Congress or most other offices."
RELATED: No one eclipses Trump at debate
But Winger cautioned that it's not as cut and dry as 47 states disallowing the move, with each state wording the laws differently.
For example, while it has been reported that Michigan would ban a third-party run, Winger pointed out that the law doesnt prevent a run as an independent, just one under the guise of another party. In Ohio, it's the opposite, added Mark Brown, chair at Capital University Law School and an attorney who has argued legal cases for minor parties and independent candidates challenging sore loser laws.
"There's precedents from just about every state that has a sore loser law that they don't apply to primaries," Winger said. "If I were Donald Trump and I knew I was going to be running outside the major presidential parties, I would not file for the Texas primary and South Dakota, and probably the Ohio one, although there's a flaw in the Ohio law."
Winger said the Ohio law specifically prohibits a sore-loser candidate from appearing as a minor candidate by petition, but minor party bids are typically nominations.
Brown said when he was doing research for Johnson's Libertarian campaign in 2012, he found five states that were actively enforcing sore loser laws. including Michigan and Mississippi. He argued an unsuccessful challenge to Michigan's law, which the court ultimately upheld in part because candidates can run as independents under the statute.
Donald Trump's rise
President-elect Donald Trump has been in the spotlight for years. From developing real estate and producing and starring in TV shows, he became a celebrity long before winning the White House.
Trump at age 4. He was born in 1946 to Fred and Mary Trump in New York City. His father was a real estate developer.
Trump, left, in a family photo. He was the second-youngest of five children.
Trump, center, stands at attention during his senior year at the New York Military Academy in 1964.
Trump, center, wears a baseball uniform at the New York Military Academy in 1964. After he graduated from the boarding school, he went to college. He started at Fordham University before transferring and later graduating from the Wharton School, the University of Pennsylvania's business school.
Trump stands with Alfred Eisenpreis, New York's economic development administrator, in 1976 while they look at a sketch of a new 1,400-room renovation project of the Commodore Hotel. After graduating college in 1968, Trump worked with his father on developments in Queens and Brooklyn before purchasing or building multiple properties in New York and Atlantic City, New Jersey. Those properties included Trump Tower in New York and Trump Plaza and multiple casinos in Atlantic City.
Trump attends an event to mark the start of construction of the New York Convention Center in 1979.
Trump wears a hard hat at the Trump Tower construction site in New York in 1980.
Trump was married to Ivana Zelnicek Trump from 1977 to 1990, when they divorced. They had three children together: Donald Jr., Ivanka and Eric.
The Trump family, circa 1986.
Trump uses his personal helicopter to get around New York in 1987.
Trump stands in the atrium of the Trump Tower.
Trump attends the opening of his new Atlantic City casino, the Taj Mahal, in 1989.
Trump signs his second book, "Trump: Surviving at the Top," in 1990. Trump
has published at least 16 other books, including "The Art of the Deal" and "The America We Deserve."
Trump and singer Michael Jackson pose for a photo before traveling to visit Ryan White, a young child with AIDS, in 1990.
Trump dips his second wife, Marla Maples, after the couple married in a private ceremony in New York in December 1993. The couple divorced in 1999 and had one daughter together, Tiffany.
Trump putts a golf ball in his New York office in 1998.
An advertisement for the television show "The Apprentice" hangs at Trump Tower in 2004. The show launched in January of that year. In January 2008, the show returned as "Celebrity Apprentice."
A 12-inch talking Trump doll is on display at a toy store in New York in September 2004.
Trump attends a news conference in 2005 that announced the establishment of Trump University. From 2005 until it closed in 2010, Trump University had about 10,000 people sign up for a program that promised success in real estate.
Three separate lawsuits -- two class-action suits filed in California and one filed by New York's attorney general -- argued that the program was mired in fraud and deception. Trump's camp rejected the suits' claims as "baseless." And Trump has charged that the New York case against him is politically motivated.
Trump attends the U.S. Open tennis tournament with his third wife, Melania Knauss-Trump, and their son, Barron, in 2006. Trump and Knauss married in 2005.
Trump wrestles with "Stone Cold" Steve Austin at WrestleMania in 2007. Trump has close ties with the WWE and its CEO, Vince McMahon.
For "The Apprentice," Trump was honored with a star on the Hollywood Walk of Fame in January 2007.
Trump appears on the set of "The Celebrity Apprentice" with two of his children -- Donald Jr. and Ivanka -- in 2009.
Trump poses with Miss Universe contestants in 2011. Trump had been executive producer of the Miss Universe, Miss USA and Miss Teen USA pageants since 1996.
In 2012, Trump announces his endorsement of Republican presidential candidate Mitt Romney.
Trump speaks in Sarasota, Florida, after accepting the Statesman of the Year Award at the Sarasota GOP dinner in August 2012. It was shortly before the Republican National Convention in nearby Tampa.
Trump appears on stage with singer Nick Jonas and television personality Giuliana Rancic during the 2013 Miss USA pageant.
Trump -- flanked by U.S. Sens. Marco Rubio, left, and Ted Cruz -- speaks during a CNN debate in Miami on March 10. Trump dominated the GOP primaries and emerged as the presumptive nominee in May.
The Trump family poses for a photo in New York in April.
Trump speaks during a campaign event in Evansville, Indiana, on April 28. After Trump won the Indiana primary, his last two competitors dropped out of the GOP race.
Trump delivers a speech at the Republican National Convention in July, accepting the party's nomination for President. "I have had a truly great life in business," he said. "But now, my sole and exclusive mission is to go to work for our country -- to go to work for you. It's time to deliver a victory for the American people."
Trump apologizes in a video, posted to his Twitter account in October, for vulgar and sexually aggressive remarks he made a decade ago regarding women. "I said it, I was wrong and I apologize,"
Trump said, referring to lewd comments he made during a previously unaired taping of "Access Hollywood." Multiple Republican leaders rescinded their endorsements of Trump after the footage was released.
Trump walks on stage with his family after he was declared the election winner on November 9. "Ours was not a campaign, but rather, an incredible and great movement," he told his supporters in New York.
Trump is joined by his family as he is sworn in as President on January 20.
Between the failed presidential campaigns of Anderson, Johnson, Lyndon LaRouche and David Duke, most states have dealt with sore loser presidential candidates and the general election bids were allowed to continue, Winger said.
"When you add them all up, practically every state is on record saying our sore loser law doesn't apply to presidential primaries," Winger said.
RELATED: Paul video shows Trump praising Democrats
Ultimately, a candidate with the resources at Trump's disposal would likely be able to mount a national third-party campaign, at least in terms of getting on the ballot, the experts acknowledged.
"If you're well-financed, it's hard, no doubt, but people have done it," Brown said. "Ross Perot did, John Anderson did it, Gary Johnson came real close to doing it recently. I think Trump could do it."
He continued: "Time, of course, is a problem, it is always is a problem. ... As a legal matter, Trump could wait until spring to make a decision. I'm not saying that's a good move strategically, but I don't think he has to make up his mind right now."