Chairman of the Prince William County Board of Supervisors Corey A. Stewart during a county hearing on immigration in 2007. (Tracy A. Woodward/The Washington Post)

A day after Corey Stewart won Virginia’s Republican primary for a U.S. Senate seat, President Trump warned voters not to “underestimate” the conservative candidate.

And he is right.

We should not underestimate Stewart. We should not underestimate his ability to stir anti-immigrant fears. We should not underestimate the dark depths of his Rolodex and who he will pull close to rally support for him. We should not underestimate the impact that his vow to run a “vicious” campaign against his Democratic opponent, Sen. Tim Kaine, will have on all Virginians.

Anyone who has watched a vicious fight up close knows that blood spatters in all directions.

Stewart, the chairman of the Prince William Board of County Supervisors, has described himself as “Trump before Trump was Trump,” and so it’s not surprising that during his victory speech he invoked the president’s popular anti-immigrant rhetoric, calling members of the MS-13 gang “animals” and leading his supporters in a chant of “Build that wall!”

Stewart, too, has risen on the backs of undocumented immigrants, touting with each political rung he has tried to climb a policy that Prince William County approved in 2007. It allowed police officers to check the immigration status of anyone they had probable cause to suspect was not in the country legally. After public pushback, it was amended so that officers could check a person’s immigration status only if the person had been arrested on a charge of violating a state or local law.

Prince William County’s vote on the immigration crackdown brought out residents on both sides of the issue. John Neri, a Manassas resident who said he is a second generation Italian American, carries a T-shirt that says, “Welcome to America Now Speak English.” (Carol Guzy/The Washington Post)

Stewart has spoken proudly of the crackdown’s results, boasting about the thousands of illegal immigrants county authorities have turned over to Immigration and Customs Enforcement.

To listen to him talk about it is to believe that the county kicked out a lot of bad people to benefit its residents.

It’s a comforting story.

But it’s just that — a story. The truth is much more complex and far from comforting.

I covered the Prince William County police and worked out of The Washington Post’s bureau in Manassas when the policy went into effect. I had gotten to know and like many officers across different ranks and saw how they were suddenly thrust into unfamiliar territory.

Arresting someone for stealing is different from asking someone walking out of a 7-Eleven for identification because you suspect he might not be a U.S. citizen.

Before the crackdown, the county police had worked hard to build relationships with the Latino community. At one point, the force even put out a news release to announce a particularly diverse class graduating from the academy. I wrote about it, noting that among the graduates, more than half spoke a foreign language. One of the graduates had come from war-torn Sierra Leone as a teenager with his mother and three brothers and had started volunteering with the department at 18 while he still struggled with English.

“I’m very please with the diversity of this group because it reflects our community,” then-Police Chief Charlie T. Deane said.

It seemed the county was trying to adapt and accommodate a changing population and landscape. It was a place where new subdivisions were sprouting next to farms and where different languages mingled daily with the Southern greetings of “ma’am” and “sir.”

It felt welcoming.

Then the crackdown came. The police, under Deane’s leadership, held community meetings in Latino neighborhoods to try to explain what the new policy entailed. The fear was that crime victims wouldn’t call the police and that witnesses would no longer cooperate.

I wrote about all that. What I didn’t write about was how it felt being a Latina in a place that was suddenly shining a flashlight at people who looked like me.

I don’t remember the day, but I know the moment it hit me that the county’s atmosphere had changed.

There was a candy store across the street from The Post’s bureau, and I decided to walk there for a quick burst of energy. As I stepped off the curb, a pickup truck sped by and the driver shouted at me, “Go back to your country!”

I looked around to make sure he was talking to me — as if it would have somehow been better if he wasn’t. And then I decided I didn’t want to spend my days anymore in a place that was feeling increasingly hostile.

That’s the side of immigration crackdowns people don’t talk about. Hate isn’t fired with the precision of an arrow. It is a shotgun blast that sprays pellets widely.

Three years after Prince William enacted its policy, it paid $385,000 for the University of Virginia to study the effects. Among the findings, according to a 2010 Washington Post article: Hispanics — most of whom were in the country legally — were avoiding the county, and it “did not succeed in implementing an immigration policy without damaging its reputation as a welcoming place to live.”

Since then, Stewart has added to his platform a defense of Confederate statues and has gained among his supporters white supremacists.

Trump was right.

Don’t underestimate Corey Stewart. Don’t underestimate the damage he can do, even if he doesn’t win the election.