Mary Trump, the niece of Donald Trump and one of his most vocal critics, has voiced her biggest worry ahead of the November presidential elections.

Mary Trump took to Substack to outline what would be a "scarier" outcome than Donald Trump returning to the White House should he beat President Joe Biden at the polls.

"The only thing scarier than the idea of my uncle being in the Oval Office again is the idea of the Republicans controlling the Senate and the House of Representatives," she wrote.

"Both, the House in particular, would very likely be filled with even more extreme sycophants who hate the Constitution with the same blind passion with which they hate women and minorities. All the worrying in the world won't stop that from happening. "

Newsweek contacted Donald Trump's representatives by email for comment.

Mary Trump detailed how the previous week in politics was a "perfect storm of horrible," including a much-talked-about first presidential debate and the U.S. Supreme Court's ruling on whether Trump has presidential immunity in the Department of Justice election interference case.

On Monday, the court ruled former presidents have absolute immunity for official acts but no immunity for private acts and ordered a lower court in Washington, D.C., to try to determine what constitutes an official act.

"The Supreme Court's immunity ruling was a chilling but compelling reminder that, while stopping Donald is our most immediate task, we also have to stop the people who enable him," Mary Trump wrote.

"They are arguably even more destructive to our country and, unlike Donald, their plans to dismantle our institutions go far beyond putting him back in the White House. Now that the Supreme Court has removed the guardrails, we need to factor in the need to build new ones. That starts by putting the same amount of care, attention, and energy into down-ballot races as we do the presidential race."

Donald Trump's niece last week described his debate performance as "apocalyptically disastrous."

On June 27, he went up against Joe Biden in Atlanta, Georgia for the first of three presidential debates. While much was said about Biden's bumbling performance, which his team blamed on a cold, Mary Trump wrote that her uncle should also be facing calls to drop out of the race.

"Let's be honest about the performance of the other person on the stage who, if the metrics by which we're measuring success are honesty, policy, a vision for America, and the defense of democracy, had a debate so apocalyptically disastrous that I can't believe that not one pundit, not one Republican official (at least none I'm aware of) has called on Donald Trump to drop out of the race," Mary Trump she wrote on Substack after the debate.

"If we're only going to count style over substance, I'll take hoarse and halting over hate-filled and unhinged every day of the week."