Bill Weld, the former Governor of the US state of Massachusetts, has announced that he was officially entering the 2020 presidential race, becoming the first Republican to challenge President Donald Trump who he thinks “mocks the law”.

“Ours is a nation built on courage, resilience, and independence. In these times of great political strife, when both major parties are entrenched in their ‘win at all cost’ battles, the voices of the American people are being ignored and our nation is suffering,” CNN quoted Weld as saying on Monday.

“It is time for patriotic men and women across our great nation to stand and plant a flag. It is time to return to the principles of Lincoln — equality, dignity, and opportunity for all. There is no greater cause on earth than to preserve what truly makes America great. I am ready to lead that fight.”

In 2016, Weld was the Vice Presidential nominee on the Libertarian Party ticket with former New Mexico Governor Gary Johnson. He previously served two terms as the governor of Massachusetts in the early 1990s.

Weld ran for the Senate in Massachusetts in 1996 and lost against John Kerry. He later moved to New York and in 2005 unsuccessfully sought the Republican nomination for governor.

Weld told CNN that it would be a “political tragedy” and he would “fear for the Republic” if the country had six more years of Trump as President.

“I really think if we have six more years of the same stuff we’ve had out of the White House the last two years that would be a political tragedy, and I would fear for the Republic,” he said.

“I would be ashamed of myself if I didn’t raise my hand and run,” he added.

Weld said he will not run as an Independent if he does not win the Republican nomination.

Trump enjoys a nearly 90 per cent approval rating among Republicans, according to Gallup.

When asked about the President’s historically high approval rating and whether he believes he can beat him in the primary, Weld said: “Yeah, I do. Particularly in New Hampshire, where I’m spending a lot of time, it’s one vote at a time and one voter at a time…”

He added that he feels Trump “mocks the rule of law”.

“I spent seven years in the Justice Department trying to keep the politics out of law enforcement, he’s trying to put it in,” Weld said.

Weld also slammed Trump’s attitude toward climate change and his confrontational style toward the press.

While Weld sees blame on both sides of the aisle for the divisiveness coming from Washington, he said Trump is the “grand master” of the problem. “I’ve never seen such bitterness in this country.”