A syringe is pictured along West Main Street in downtown Austin, Ind., in Scott County on Tuesday, March 24, 2015. (AP Photo/News and Tribune, Christopher Fryer)

A drug-related HIV outbreak in rural Indiana has prompted Indiana Gov. Mike Pence to declare a public health emergency and take the unusual step of instituting a 30-day needle exchange program in the hardest-hit area. Needle exchanges allow intravenous drug users to trade in used needles for sterile ones. There's widespread evidence going back decades that such programs are effective at preventing the spread of HIV and other blood-borne diseases, that they encourage drug users to seek treatment for their addictions, and that they do not promote or encourage drug use overall.

Still, Pence (R) is no fan of these programs. "In response to a public health emergency, I'm prepared to make an exception to my long-standing opposition to needle exchange programs," he said. In the span of one extraordinary sentence, Pence both acknowledged the programs' efficacy and reiterated his opposition to them.

[Read: Indiana is battling the worst HIV outbreak in its history]

But Pence is hardly alone on the issue. According to law professor Scott Burris of Temple University, 24 states -- mostly red ones -- don't allow the practice. Federal funding for needle exchanges has been banned since 1980. Congress lifted the ban in 2009, but House Republicans reinserted it into a 2012 spending bill, and it has remained in place.

Critics of needle exchange programs maintain the position that the programs "encourage drug use," but, if anything, such programs do the exact opposite. They allow contact between public health officials and communities of addicted people who are otherwise nearly impossible to reach. If you can get IV drug users to come in to exchange needles, you can also talk to them about resources available to help them quit using altogether.

If the decades of research refuting the canard about promoting drug use aren't enough for you, here's a simple thought experiment: Let's say your county suddenly began providing sterile needles to IV drug users. Would you be tempted to start using heroin as a result? (Spoiler: No, you wouldn't.)

On a gut level it's easy to understand why policymakers might feel squeamish about needle exchanges. Giving needles to a drug addict may feel like putting a gun in the hands of a person determined to harm himself. U.S. Rep. Hal Rogers (R-Ky.) has said that he is "concerned that needle exchange programs only encourage drug addicts to remain addicted to drugs and perpetuate the cycle of drug crime."

Caution in the face of a controversial topic is a reasonable response. But there is no controversy when it comes to syringe exchanges. None. Zero. Rogers, Pence and their colleagues needn't be concerned -- they only need to look at the evidence compiled by public health officials that show that these exchanges are safe and effective, and that they don't "encourage" more drug use. Needle exchanges have been endorsed or supported by the federal Substance Abuse and Mental Health Services Administration, the Centers for Disease Control, the U.S. Surgeon General, the World Health Organization, the American Medical Association, the White House Office on National Drug Control Policy, the National Institutes of Health, the United Nations Office on Drugs and Crime, and the list continues but in the interest of space I'll stop there.

Pence's 30-day moratorium on needle exchange restrictions is a necessary step in the right direction, but it is by no means a sufficient response to the HIV outbreak in Indiana. The program will need to be broadened after 30 days. Exchanges need to be continuous  to be effective -- otherwise, people will just go back to using dirty needles when the program expires.

With any luck, after 30 days pass without the sky falling in, Pence may be inspired to reconsider his opposition to the programs. But his legislature is already one step ahead of him: A bill to broaden the exchange program passed an Indiana House committee Monday.