(Facebook/kevin nicholson and Getty)

The frontrunner for a Republican US Senate nomination has seen his parents donate the maximum amount allowed – to his potential Democratic opponent.

Kevin Nicholson is running for the Wisconsin Senate seat currently occupied by Tammy Baldwin, who became the first openly gay US Senator in 2013.

But months after he announced his candidacy in the Republican primary, his parents donated as much as they could to Baldwin.

In December, Donna and Michael Nicholson each contributed $2,700 to Baldwin for her re-election campaign, according to CNN.

In response, their 40-year-old son distanced himself from them.

“My parents have a different worldview than I do, and it is not surprising that they would support a candidate like Tammy Baldwin who shares their perspective,” he said.

Nicholson was at pains to emphasise that his political outlook should not be in any way associated with his upbringing.

“I’m a conservative today not because I was born one, but because of the experience I earned as a Marine in combat, my experience as a husband and father, my choice to be a Christian, the schools I chose to attend and the decision to pursue the career that I have,” he said.

“Regardless of who may disagree with my life decisions, I would not trade these experiences for anything, and they will always guide my views as Wisconsin’s next US Senator.”

Nicholson has previously tweeted his joy over gaining support from Steve Bannon, who left his position as President Donald Trump’s chief strategist in August.

“Excited to receive an endorsement from the Great America PAC and Steve Bannon,” Nicholson wrote.

Bannon, a strong opponent of LGBT rights and the former head of far-right news outlet Breitbart News, was seen as the driving force behind Trump’s controversial Muslim travel ban.

In September, it was revealed that he had secretly corresponded with representatives of an anti-LGBT hate group.

Nicholson’s political leanings have come a long way since he was elected as president of the College Democrats of America in his early 20s.

He had a full-time position on the Democratic National Committee and even took a speaking slot at the party’s national convention in 2000.

In that speech, he tells the crowd in Los Angeles: “We care about a woman’s right to choose.”

He adds that “we know the importance of preserving our environment,” before praising the Democratic presidential ticket of that year, Al Gore and Joe Lieberman.

Nicholson then pleads with the crowd, in reference to the Republican presidential candidate George W Bush, “don’t let future generations look back and call us Generation Dubya.”