Donald Trump has continued being a highly-polarizing figure. That includes inside the Republican Party. Even among Trump's supporters, a large number of people want there to be viable alternatives in a primary.

Whether they're successful or not, a number of challengers have entered the race. The most recent is Mark Sanford, a former U.S. representative and governor of South Carolina. Politico reports that Sanford thinks the party has lost its way. But he's also not without controversy, both personally and politically.

He first entered politics 25 years ago

Sanford is a native of Fort Lauderdale, Florida. When he was a teenager, he and his family moved to a farm in Beaufort County, South Carolina. He graduated from Furman University in Greenville, South Carolina and from the University of Virginia business school. Eventually, Sanford settled in Sullivan's Island, South Carolina. He also founded a real estate investment company.

In 1994, Sanford was elected to the U.S. House of Representatives from South Carolina's 1st District. The year would prove to be highly successful for Republicans across the country. He was re-elected twice and earned a reputation as a staunch fiscal conservative.

Sanford chose not to run for re-election in 2000.

He would join the US Air Force Reserve and serve for roughly a decade. He retired with the rank of captain.

In 2002, Sanford was elected governor of South Carolina. He defeated the incumbent, Democrat Jim Hodges. Although the state legislature was also controlled by Republicans, Sanford was frequently at odds with its members.

The most famous incident of this is likely Sanford's attempt to reject stimulus money from the federal government. The state's Supreme Court eventually ruled that Sanford did not have the authority to do so.

He was re-elected in 2006. But his second term would be cut short amidst personal scandal. A bizarre story involving the Appalachian Trail and Argentina led to Sanford admitting to infidelity.

He was censured by the legislature and ultimately resigned. The scandal also, perhaps more so, impacted Sanford's personal life. His twenty-year marriage was destroyed. He and his wife had four sons together.

Following his resignation, Sanford moved to Charleston, South Carolina. He decided to start living a more spiritual life and also became a Fox News contributor. In 2013, Sanford's old seat in Congress opened up. Its holder, Tim Scott, was appointed to the U.S. Senate after Jim DeMint resigned. Sanford chose to run won the race for the seat. Again, he was re-elected twice.

He would frequently openly disagree with President Trump, drawing Trump's ire. This was possibly the key factor in Sanford being defeated in the Republican primary for his seat in 2018.

State Representative Katie Arrington, a staunch Trump supporter, was nominated instead. However, Arrington lost in the general election to Democrat Joe Cunningham. It marked the first time in 40 years that the seat went Democratic.

Sanford's path to the nomination was recently made more difficult by his home state. As Axios reports, South Carolina, along with Kansas, has taken their primary selections out of the hands of voters. The move is to try to shield Trump from having to face any significant challenges.

At least two others in the field

Two others announced a challenge to Trump for the Republican nomination before Sanford. The first was Bill Weld, a former governor of Massachusetts and vice presidential nominee of the Libertarian Party.

Joe Walsh, a conservative commentator and former U.S. representative from Illinois, was the second.

Others may also announce their candidacy. Many commentators have been speculating about John Kasich. Kasich is a former governor of Ohio and member of the U.S. House of Representatives, chairing its Budget Committee. He also ran against Trump, among others, for the Republican presidential nomination in 2016.