There are many things that President Donald Trump and the people of the city of Chicago disagree about, but a desire to reduce the city’s violence and homicide levels is not one of them. How this could be accomplished, however, is a different story.

After the president tweeted that he would "send in the feds" to Chicago last week, White House Press Secretary Sean Spicer elaborated slightly, saying that Trump would provide “aid, if it was requested up through the governor, that the federal government can provide on a law enforcement basis”—potentially referring to the National Guard, which either the president or the governor can mobilize.

It's not a great idea, as several Chicago writers, and even Governor Bruce Rauner, have pointed out for various reasons: National Guardsmen aren’t cops and know nothing about law enforcement; they don’t have the power to arrest people, and as such, generally act as an occupying force when they are called in. Mayor Richard J. Daley called them to Chicago twice in 1968. Both times they clashed violently with protesters.

Spicer also mentioned “other aid” that could be “extended through the U.S. Attorney’s Office”—another law enforcement agency—“or other means,” though he did not elaborate further. So, what are some "other means" to which federal officials can help Chicago reduce violence? We talked to the experts and got some suggestions of methods that have succeeded in the past.

A Proven Anti-Violence Program

In 2000, the year 631 homicides were committed in Chicago, public health expert Gary Slutkin launched CeaseFire, a program that dispatches health workers and former gang members into communities to detect and prevent violent conflicts before they escalate. The program proved highly effective, according to internal and external evaluations, and became the subject of the award-winning documentary The Interrupters in 2012.

Even so, Rauner froze state funds for CeaseFire in 2015, and the group's parent organization, Cure Violence, published a report in September calling attention to the direct correlations between its funding and the city’s homicide rates. (The program has reported similar findings in Baltimore, New Orleans, New York, Kansas City, and Philadelphia.)

CeaseFire's track record shows that it “warrants emergency funds” from the federal government, says Charles Ransford, the senior director of science and policy at Cure Violence. “This is the sort of thing that the federal government does when we have outbreaks of contagious problems,” Ransford explains. “A good example of this is Ebola. The federal government dedicated emergency funds so we could have a bunch of health workers working to stop Ebola from getting out of control and escalating.”

The Department of Justice could fully fund CeaseFire across the city for three years at $15 million a year, Ransford says, which he anticipates would get the annual homicide count to below 400, based on the group's internal data.

A Massive Public Works Project

One feature of Chicago’s rising shooting rates is that the vast majority of incidents take place in low-income neighborhoods on the city’s South and West Sides. The concentration of poverty in these pockets of the city is no coincidence; in the late 1990s and early 2000s, the Chicago Housing Authority’s “Plan for Transformation” destroyed public housing projects and scattered poor residents across the city. Many of those who received housing vouchers were economically forced into areas with rising crime rates, and a large influx of relocated-via-voucher residents correlates with an influx in violent crime, studies show.

“In the ‘90s in Chicago, we took money away from public housing and put it in law enforcement… it didn’t work out at all,” says University of Illinois at Chicago criminology professor John Hagedorn. He says that stable housing plays an essential role in reducing violence. For example, he cites New York City, which heavily invested in its existing public housing stock in the 1990s with success. That investment, paired with city-funded anti-violence programs like CeaseFire and effective policing, helped drive down violent crime at the notorious Queensbridge Houses to the point where there were zero shootings in 2015.

Hagedorn proposes a massive federal public-works project to rebuild public housing in neighborhoods with high violence rates. The initiative also should focus on creating jobs—a recent study found high unemployment among young people on the South and West Sides is linked to violence—using resources from educational hubs like the University of Chicago and University of Illinois Chicago.

Unfortunately, according to Center for Tax and Budget Accountability senior policy analyst Daniel Kay Hertz, there is little that President Trump could do to force the CHA to emulate New York’s public housing policies. The voucher agreement between the U.S. Department of Housing and Urban Development and the CHA stipulates that the CHA can use the money as it sees fit, and a law passed by Congress in 2015 automatically renewed the contract without any negotiations. According to a CTBA report released this month, the CHA spends a considerable amount of the federal voucher money it receives on paying off its bond debts, instead of working to house the over 119,000 households on its waiting list.

A Boost to Health Care

There is a great irony in the gap between Trump’s stated health care policies—repealing the Affordable Care Act—and his apparent concern for Chicagoans’ health and wellbeing. The “biggest thing the federal government” can do to keep residents safe would be to preserve ACA expansions that ensure medical coverage (including substance abuse and mental health treatment) for people in the criminal justice system, according to Colleen Grogan, a professor at the University of Chicago’s School of Social Service Administration. Providing these types of care to former prisoners is shown to reduce their chance of committing crimes after being released.

Nonpartisan public health experts have indirectly linked inefficient mental health care in poor communities of color with increased violence. Residents at community forums or health care meetings often say they are most concerned about the lack of mental health care, Grogan says—to the point where they will tax themselves even more to see that it is provided.

To reduce violence rates, President Trump could direct the federal government to provide mental health care through publicly subsidized clinics—especially needed after Mayor Emanuel closed six of them without explanation in 2012. For an even more immediate impact, Grogan says Trump could give extra funding and support to community hospitals on the South and West Sides, which don’t have specialized trauma units in which to treat gunshot victims. Studies have shown that proximity to trauma centers in Chicago directly correlate to whether a gunshot victim will likely survive or not.

A Limit to Gun Trafficking

Based on his previous statements, this is the proposal least likely to attract Trump’s support, despite the fact that it’s heartily endorsed by two of America’s largest policing organizations: Pass a significant anti-gun trafficking law that would staunch the flow of legal weapons from Indiana to Chicago. Our proximity to the state border makes it remarkably easy to transport legally bought guns across; per a Chicago Police Department report, guns from Indiana were used in nearly 20 percent of gun crimes in 2014. Law enforcement officials have repeatedly said that cutting the city off from that market would save Chicagoans’ lives.