President Trump has talked a lot about defeating “radical Islamic terrorism.” Yet which groups fall into that category?

The Islamic State certainly does. But what about the Muslim Brotherhood? Its brand of Islamism means it is certainly no ally to us. Yet how to respond to the Brotherhood is in some ways even more complex than how to respond to ISIS.

The Muslim Brotherhood was formed in Egypt in 1928 by Hassan al-Banna. A schoolteacher, al-Banna believed that Muslim societies were declining in the face of Western secularism. He dreamed of a restoration of pure Shariah law and an Islamic caliphate.

He founded the Muslim Brotherhood as an organization dedicated to Islamizing society, with a vision of applying Islam as an all-encompassing political system. What began as small gatherings and lectures at mosques and coffeehouses over time transformed into Islam’s largest religious and political network.

In their desire for a caliphate and application of Shariah, the Brotherhood shares certain characteristics with Salafi jihadi groups such as al Qaeda. Indeed, the Brotherhood once possessed an armed wing, and Brotherhood offshoots are now designated terrorist groups. Legislation introduced in the Senate calls for officially designating the Brotherhood as a foreign terrorist organization.

Yet today’s Muslim Brotherhood is more equivocal about when and where acts of violence should be carried out, and its ties to terrorism in the West are not clear-cut. It still wants to Islamize society and continues to make excuses for certain terrorist movements, encourages religious segregation and champions a reactionary interpretation of faith over a sense of citizenship. This is all deeply unpleasant — but in a free society, such opinions are within the boundaries of the law.

So what can the U.S. do? The first step is to get its own house in order.

The Hudson Institute’s Zeyno Baran and other scholars note that the Muslim Brotherhood has had a presence in the U.S. since the 1960s. In recent years, several groups associated with the Brotherhood have come under legal scrutiny. The North American Islamic Trust, the Islamic Society in North America and the Council on American Islamic Relations were listed as unindicted co-conspirators in a major terrorist financing trial that led to a spate of convictions concerning the funding of Hamas, the Palestinian terrorist outfit closely tied to the Brotherhood.

Despite this, CAIR has since been hosted at the White House and worked alongside the FBI and the Department of Homeland Security.

To help resolve these types of issues, the U.S. should establish a commission to conduct a thorough, up-to-date review of the Brotherhood’s activities in the U.S. and investigate the foreign ties of Brotherhood-linked groups operating domestically. While this commission does its work, government agencies should adopt a safety-first approach and stop all engagement with domestic groups historically tied to the Brotherhood.

Admittedly, this is hazardous terrain for lawmakers, who quite understandably desire to engage with Muslim communities in their states and districts. For one thing, Islamist groups muddy the waters by establishing front groups, making it harder to assess their ideological leanings. Furthermore, there will be media resistance; inevitably, many will dub the commission an Islamophobic witch hunt. Objections may also come from those who still subscribe to the notion that the Brotherhood can be used as a firewall, a safe outlet for venting radical Islamist sentiments that could otherwise manifest themselves in terrorist attacks.

This is perhaps the most insulting idea of all. Anyone suggesting that the Ku Klux Klan could be used by the U.S. government as a firewall to prevent far-right terrorism would be laughed out the room. It does a great disservice to American Muslims to treat them differently.

It also does them a great disservice to suggest that the Brotherhood’s extreme ideology is anything other than a fringe opinion here in the U.S. The Muslim Brotherhood is not the gatekeeper to majority Muslim opinion that its leaders like to pretend they are. The key is making sure it stays that way.