Just when you think you've hit bottom with Donald Trump, the trapdoor opens. Trump now demands a religious test for entering America, calling for a "total and complete shutdown" of Muslims entering the United States.

Trump justified the extreme measures with a blanket statement of the "great hatred" felt by "large segments of the Muslim population" toward Americans. The comments evoked strong fear of reprisals in the American Muslim community.

This was the last straw for many of Trump's GOP rivals. "Donald Trump is unhinged," said former Florida Gov. Jeb Bush. "You don't need to be banning Muslims from the country," said N.J. Gov. Chris Christie. That's a ridiculous position."

The country is understandably on edge after last week's mass killings in San Bernardino, California. But Trump seems to delight in playing on people's fears.

Trump hit a new low by mocking a disabled New York Times reporter. Though he later denied the repulsive act, it was clear to anyone who saw the video.

His pattern of bullying minorities, women and now disabled people is undeniable, yet Trump still leads in the GOP presidential polls.

"Trump's like Biff from 'Back to the Future,'" said comedian Holly Walker on "The Nightly Show with Larry Wilmore." "People want to be on the side of the rich bully."

According to Bob Gale, writer of "BTTF Part II," blowhard Biff using profits from his 27-story casino to influence the GOP in the movie was, indeed, inspired by the Donald.

Trump is a charismatic, TV-savvy guy who speaks his mind. Some admire him because he's not politically correct. I agree -- smearing Muslims, calling women disparaging names and mocking disabled people is far from P.C. It's also far from right.

Still, his poll numbers keep rising. But let's remember that we're talking about roughly one-third of Republicans, a small percentage of the nation. Some polls show a majority of Americans don't consider Trump qualified to be president. Perhaps it's time for the saner voices in the GOP to figure out why this demagogue is so popular with a significant percentage of their voters.

Trump can be a humorous, entertaining guy. But spreading fear and hatred is far from funny.

Playwright Mike Vogel blogs at newyorkgritty.net.