Donald Trump in his first interview since Election Day on Sunday

President Trump blasted judges' rejections of his legal challenges to 2020 election results and said he couldn't be certain any of his cases would make it to the Supreme Court in his first interview since Election Day on Sunday.

"We’re not allowed to put in our proof. They say you don’t have standing," Trump told "Sunday Morning Futures." "I would like to file one nice big beautiful lawsuit, talking about this and many other things, with tremendous proof. We have affidavits, we have hundreds and hundreds of affidavits."

"You mean as president of the United States, I don't have standing? What kind of a court system is this?" Trump continued.

Most recently, the Pennsylvania Supreme Court dismissed a case Saturday night brought by Rep. Mike Kelly, R-Pa., and a handful of other Republican voters who sought to overturn last year's law creating no-excuse mail-in voting as well as halt further action in certifying Pennsylvania's votes.

"We're trying to put the evidence in, and the judges won't allow us to do it," Trump said. "We have so much evidence. You probably saw Wednesday last week we had a hearing in Gettysburg, Pennsylvania. … Unbelievable witnesses, highly-respected people, that were truly aggrieved."

Trump added that he was "ashamed" he endorsed Republican Georgia Gov. Brian Kemp after Kemp certified the state's presidential election results in favor of President-elect Joe Biden. Kemp also called for an audit of the votes. Trump has yet to concede the 2020 election, even as Biden announces Cabinet members and plans for when he takes office in January. "My mind will not change in six months. There was tremendous cheating here," Trump warned. "If Republicans allow it to happen, you’ll never have another Republican elected in the history of this country, at a Senate level or at a presidential level."

Judge Ken Starr said the president's path to victory is fading despite "numerous" examples of anecdotal evidence.

"But the difficulty now is translating those allegations, intuitions and the reports into actual admissible evidence in court," Judge Ken Starr told Fox News on Sunday. "Rudy [Giuliani] in the Pennsylvania litigation ... said according to the opinion, this case is not about fraud. Well, at this stage we need to have the evidence."