Here are 5 troubling omens that should make you nervous about Trump's Arizona rally tonight

President Donald Trump is holding a campaign rally in Arizona on Tuesday evening -- and there are already worries that he could use the rally to make more incendiary statements that could further inflame racial tensions in the United States.

While there is no way of knowing exactly what the president will say, there are already troubling omens that he will do something to set off yet another firestorm of controversy.

Below are five ominous signs about what's to come in Arizona on Tuesday night.

1.) Phoenix's mayor has asked Trump not to come -- and has been ignored. Democratic mayor Greg Stanton wrote an op-ed for the Washington Post this week asking Trump not to come to his city on Tuesday.

"Trump has doused racial tensions with gasoline," Stanton said. "With his planned visit to Phoenix on Tuesday, I fear the president may be looking to light a match."

Trump has ignored this plea.

2.) Trump has already floated the idea of pardoning racist former Sheriff Joe Arpaio, who was found guilty earlier this year of criminal contempt over violating a court order that mandated that he stop his program of racial profiling.

Fox News reported earlier this month that Trump is "seriously considering a pardon for Sheriff Arpaio," whom he praised as a "great patriot" who has done "a lot in the fight against illegal immigration."

3.) Multiple protests against Trump are planned -- and they could be targeted by Trump supporters. Multiple demonstrations are planned for Trump's visit to Phoenix, including protests with titles such as "No hate in our streets" and "Protest and resist the dictator." Given clashes in Charlottesville between white nationalists and counter demonstrators, similar violence could play out on the streets of Phoenix.

4.) Trump's ego is hurting -- and he's desperate for applause from his base. Trump has had a very rough summer politically, and his approval rating at the moment stands below 40 percent. This might make the president more likely than ever to gin up enthusiasm from the crowd by playing to its base instincts -- even if that means fueling racial tensions.

The New York Times' Maggie Haberman reports that Trump's daughter-in-law Lara has cut a radio ad asking people to show up for Trump's big Arizona rally -- an indication that the president fears the rally will not have strong attendance.

5.) There are rumors Trump might try to boost minority turnout at his rallies with the help of paid supporters. A Craigslist ad posted on Sunday sought actors to pose as Trump supporters to attend his rally this week.

The ad, which was deleted 30 minutes after posting, said that "minorities especially desired to hold pro-Trump signs, cheer on command, and show diversity."

It is unknown if this ad was real or a prank, however, as anyone can post an ad on Craigslist for any reason.