Former South Carolina Governor and U.S. Representative Mark Sanford says he will challenge Donald Trump for the Republican nomination in 2020.

A former governor best known for his 'Appalachian Trail' cheating scandal, Sanford lost his congressional election last fall after Trump lobbed a personal attack on him hours before the polls closed.

He has been gearing up for a presidential bid since July but told DailyMail.com in a phone call that he does not have a campaign staff or national infrastructure in place, yet.

'I'm just taking it a day at a time. This is a daunting task. I've acknowledged - I get all the different things that make it Herculean, and David and Goliath and all those sorts of things,' he said. 'But you know, all you can do is what you can do, and today was about planting a flag.'

He could not provide a timeline for an acceleration, days after Republicans in his home state said they're cancelling the South Carolina primary and awarding every delegate to the sitting president.

Sanford said the move was 'at least suspect' but 'not determinative' to his decision to compete.

A senior Trump campaign official meanwhile asked DailyMail.com, 'Who?' in a text message asking for a comment on Sanford's entry into the race.

Former South Carolina Governor Mark Sanford announced Sunday he will be challenging Donald Trump in the 2020 Republican primaries

Sanford said he planned to announce his long shot bid in his home state of South Carolina and was deterred by Hurricane Dorian, which made its way up the coast this week.

He'd given himself a Labor Day deadline to make a decision, but told DailyMail.com on Sept. 1 that he would not make an announcement amid the storm that threatened to ravage parts of the American south.

After South Carolina and two other states said this week that they were cancelling their primaries, in favor of awarding all their delegates to Trump, the odds that Sanford would be able to mount a successful challenge to the incumbent president dimmed significantly.

However, he announced on Sunday that he'll do it anyway, to force a national conversation on the principles the Republican Party.

'I'm here to tell you right now that I'm going to get in,' Sanford declared in a 'Fox News Sunday' interview, ending speculation about a potential candidacy.

He said he was running because he felt 'as a Republican Party, we have lost our way.' Sanford specifically noted that the party is wavering on fiscal conservatism.

Asked by DailyMail.com in a subsequent phone call what his 'goals' were for his campaign, Sanford first said he wanted to draw attention to ballooning federal spending. He mentioned winning as a secondary objective.

'We've got multiple goals. First is can we infuse the debt/deficit/spending conversation into this national debate that we have once every four years, that's currently not being talked about,' he replied. 'Two, is can we win and do something about it.'

Kansas and Nevada joined South Carolina this week in ditching their Republican nominating contests, to the the disadvantage of Sanford and two other politicians trying to take down Trump using the party apparatus.

Sanford was cautious about deriding Republican Party officials in the state he represented in Congress until earlier this year but said, 'It's at least suspect.'

'When you have somebody who allegedly has a 90 percent approval rating, and yet state parties are going to fairly great lengths to make sure that there's not a competition within their state,' he said of Trump's support among GOP voters.

He said that South Carolina's decision to cancel its election is especially concerning, given its status as one of the first states each presidential cycle to cast ballots.

'It is what it is. But it certainly doesn't signal strength,' he offered. 'Again, at the end of the day it was not determinative for us. What we hope to foster is a much larger national debate.'

Donald Trump referred to his Republican rivals as the 'Three Stooges' in a tweet last month

He touted his 94 per cent approval in the GOP while bashing those who dared to enter the primary race to replace him in the 2020 general elections

Sanford suggested that Trump's favorability is softer than survey suggest, arguing that pollsters who ask if Republicans would be open to supporting another candidate get significantly different results.

Whether Sanford is the candidate to cut through that support, even he admitted, 'We'll find out.'

'We have a loosely banded group of volunteers,' he said of his internal organization, claiming that he would have tripped critical wires, if he'd made staff hires before his official announcement. 'I think we'll take it to a more formal level going forward, and that will take some time.'

He noted that he won reelection several times, before he didn't, and said he's comfortable with the current approach to his candidacy.

While touting extremely high approval within the Republican Party, Trump dismissed Sanford and the two others who have launched primary challenges – Former Illinois congressman Joe Walsh and former Massachusetts Governor Bill Weld – as a joke, dubbing them the 'Three Stooges.'

'Can you believe it? I'm at 94% approval in the Republican Party, and have The Stooges running against me," he tweeted in late August.

'One is "Mr. Appalachian Trail" who was actually in Argentina for bad reasons," he said in reference to Sanford.

'Another one is a one-time BAD Congressman from Illinois who lost in his second term by a landslide, then failed in radio,' he said in reference to Walsh.

'The third is a man who couldn't stand up straight while receiving an award,' he said, referencing Weld. 'I should be able to take them!'

In July, Sanford floated the possibility that he would enter the 2020 race as an opponent to President Trump.

'Sometimes in life, you've got to say what you've got to say, whether there's an audience or not for that message,' he told the Post and Courier earlier this summer.

The Trump campaign's response at the time was: 'Whatever.'

While serving as governor of South Carolina, Sanford was embattled by a scandal where for six days he was unaccounted for.

His aides chalked up the disappearance in June 2009 to a hike on the Appalachian Trail.

Former U.S. representative from Illinois Joe Walsh (left) and former Massachusetts Governor Bill Weld (right) already announced earlier this summer that they are running in the 2020 Republican primary

The then-governor ended up confessing during a teary-eyed news conference that he was actually meeting up with a woman he'd been engaging in an extramarital affair with. Sanford and his wife, Jenny, soon divorced.

He later proposed to girlfriend Maria Belen Chapur, before an extremely public breakup in 2014, when he penned a 2,400-word Facebook post expounding on the status of their relationship.

Sanford served in the House of Representatives from 1995-2001, and then as South Carolina governor after that until 2013, when he was elected to Congress again, before being pushed out in the 2018 midterms.

The Republican politician is a vocal critic of Trump, and the president publicly rejected and campaigned against the then-incumbent representative in his primary last fall, contributing to the Republican losing his seat in the 2018 midterm elections.

He lost in the June 2018 primaries to Katie Arrington, who was later defeated by Democrat Joe Cunningham.

Trump attacked Sanford at the time as 'very unhelpful to me in my campaign' and 'nothing but trouble.' He mocked Sanford's political scandal, claiming he disappeared to hike the 'Tallahassee Trail,' misstating the name of the footpath.

Sanford is the third Republican to launch a primary challenge against Trump this cycle after Walsh and Weld announced earlier this year.