A close relative of former President Richard Nixon is for the first time publicly discussing the disgraced prez’s resignation over Watergate — and says it reminds him of how unfairly Donald Trump is being treated today.

Nixon’s son-in-law Ed Cox, who is chairman of the New York Republican Party, claimed Sunday that his late father-in-law was railroaded at the time by an iron-clad Democratic-run Congress and a much more centralized, liberal-dominated media.

Cox — asked on 770 WABC’s  “The Cats Roundtable” if the push to force out Nixon has similarities to the Democratic prosecutions of Trump — replied, “Absolutely.”

“[Trump’s] two impeachments — certainly with lawfare,” said Cox, who married Nixon’s daughter Trish in 1971, referring to partisan prosecutions.

Nixon was tied to the infamous Watergate hotel break-in and its eventual cover-up, which were carried out by GOP operatives against Democratic foes in 1972.

He resigned from office Aug. 8, 1974, during famous impeachment hearings against him that were set to help boot him from the White House. He died April 22, 1994.

Trump has been impeached twice: in 2019 for allegedly trying to pressure Ukrainian President Volodymyr Zelensky to announce investigations that would boost Trump’s campaign against President-elect Joe Biden, and in 2021 over his role in the Capitol riots.

Cox said Trump was eventually acquitted of the charges because of Republican strength in the Senate –and will beat the other pending partisan political criminal prosecutions against him. Trump is the Republican nominee for White House in a comeback bid.

“It’s happening again, but this time it’s not succeeding,” he said of Dem efforts to derail Trump.

“We have control of one House of Congress, the House of Representatives thanks to New York,” he said referring to GOP wins in the 2022 elections. I don’t think [Democrats] will succeed with respect to President Trump. He has the tools available to him that President Nixon didn’t have.”

Cox recalled how Trump told him and his wife Trisha that Nixon could have saved his presidency if he fought impeachment.

“Trisha and I were at Bedminster, President Trump’s place here in New Jersey. President Trump was there, Cox recalled. “He looked at Trisha, and he said, ‘If your father had fought, he would have won.”

“I said, ‘But Mr. President, both houses were controlled completely by the Democrats.’ And he said, ‘Oh.’

“[Trump] had both houses controlled by the Republicans in his first two years,” Cox noted. “The minority [under Nixon] had been in the minority, the Republican minority, for 40 years. They had developed … Stockholm Syndrome.”

“They were not strong as a minority in the House of Representatives and the Senate. They couldn’t stand up to the majority. And the national press was monolithic and Democratic. … There was no Fox News back then. There was no other outlet that would be supportive of a Republican president.”

“[Trump] has the tools available to him that President Nixon didn’t.”

Cox said watching his father-in-law resign was heartbreaking.

He and wife Trisha stood behind Nixon when he gave his resignation speech on TV and joined him on Marine One when he departed the White House.

“[Nixon[ saw it as a Greek tragedy because he didn’t understand … forces that were bigger than him were at work. But he knew, for the good of the country, he had to resign,” Cox said.

“[Nixon] did not expect impeachment. It had never happened before where a president had to resign or left office because of an impeachment.”

Cox said he tried to be upbeat and cheer up his father-in-law during the helicopter ride leaving the White House.

“The helicopter took off, and I was sitting opposite President Nixon. We go by the Washington Monument, and I was thinking, ‘What do I say to him under these circumstances?’ It occurred to me, this is a person who always wanted to do more for his country. He had a lot more left in him, so I said, ‘Mr. President, in 10 years, you will be back.'”

Twelve years later, Nixon was on the cover of Newsweek with the headline, “He’s Back.”

He ended up frequently consulted by successive presidents and world leaders, with Cox noting Nixon had met with some dignitaries at his and Trisha’s Manhattan residence.

A foreign-policy hawk, Nixon wasn’t afraid to take risks. He surprised the political world by visiting communist China as president.

He also passed liberal legislation, signing the Clear Air to combat pollution.

Some of the decisions cost Nixon support within his own Republican Party, but he thought they were the right thing to do, Cox said.