Hundreds of Trump supporters stormed the U.S. Capitol yesterday, halting the formal electoral college vote count by Congress and creating widespread disorder in the nation’s capital. Though the Department of Defense initially rejected a request from the District of Columbia, on Wednesday afternoon, Acting Secretary of Defense Christopher Miller approved the mobilization of the full D.C. National Guard contingent — 1,100 troops. The governors of Maryland, Virginia and New Jersey also approved activations of their own troops to support the D.C. National Guard, with more states expected to follow suit.

What does this mean? Here are three things to know.

1. Trump will not personally command the D.C. National Guard

Control of the National Guard operates differently in the District of Columbia than in the 50 U.S. states. Because of the capital’s unique status, the president serves as commander in chief of the D.C. National Guard. In practice, however, command authority has been delegated through the Secretary of Defense to the civilian Secretary of the Army for the Army National Guard and the Secretary of the Air Force for the Air National Guard. Upon request, other states — like Virginia — can augment the D.C. guard.

Since these personnel likely will fall under local control, the Posse Comitatus Act, which prevents the president from using active-duty troops to enforce domestic law, will not apply. National Guard members can support local and federal police and carry out law enforcement activities that help restore order. The Secretary of Defense has the authority to activate the D.C. National Guard on his own, but he did consult Vice President Pence. The fact that Trump was not involved suggests he was “missing in action” amid a national crisis. While the Secretary of the Army will exercise command authority, President Trump or the acting Secretary of Defense will have opportunities to inject themselves into the decision-making process, where they might direct troops to either stand down or even support protesters. Trump’s recent purge of Pentagon leadership means that some Trump loyalists may be in position to try to shape decisions. However, they have little formal and practical authority to do so.

As we saw during the widespread outcry to the White House decision to clear Lafayette Square in June, attempts to use the National Guard for partisan purposes would be highly controversial, drawing criticism as well as resistance from uniformed military leaders. If Trump or Miller issues an order that would politicize the response, they will incur significant political costs, even if the order is ultimately unsuccessful.

There are still two weeks left in Trump’s term, and any attempt by the White House to use armed forces to undermine a peaceful transition could result in another impeachment inquiry from Congress — or prosecution after Trump leaves office. Other Republicans would likely seize an opportunity to ostracize and reject the president after his term has expired. Still, while the costs of trying to use the military to stay in power probably far outweigh the potential benefits for Trump, he has not always demonstrated a strong understanding of cost-benefit analysis.

2. The U.S. military will not follow illegal orders

The National Guard has stepped in to serve as law enforcement before, especially when local police become overwhelmed and outnumbered, as appears to be the case in Washington now. However, their role is limited. If President Trump attempts to order the military to help protesters trying to interfere with normal election certification proceedings, senior military leaders would likely interpret it as an illegal order.

If that is the case, they are likely to refuse to comply. Although Trump has installed multiple loyalists over the last couple of months in the Department of Defense, orders will not work unless uniformed officers obey them. In August, the most senior military officer in the United States, Chairman of the Joint Chiefs of Staff Mark Milley, testified that the military would reject unlawful orders and support the peaceful transition of power.

3. Still, there are risks

The more serious risk is that most National Guard personnel are not trained as police. An aggressive mistake, a fearful escalation or inadvertent provocation by a National Guard soldier who is unprepared for a difficult situation could spark a crisis.

In 1970, members of the Ohio National Guard shot 13 unarmed students at an antiwar gathering at Kent State University, leaving nine wounded and four dead. National Guard personnel are also not necessarily familiar with local laws. As a result, they could be more likely to violate citizens’ rights or find themselves in situations where they have a hard time knowing whether an order is lawful or not. We saw this in June, when a military helicopter hovered over peaceful protesters near the White House, in part due to ignorance of laws and regulations.

However, recent police violence and indiscipline in the United States have led some analysts to speculate that National Guard troops might actually show more restraint than ordinary police. The National Guard response could become even more challenging if counterprotesters take to the streets to push back against Trump’s supporters.

Was the Department of Defense prepared?

Many scholars have predicted election-related violence for months, and the president’s focus on Congress’ meeting to certify the electoral college results on Wednesday provided a clear focal point for trouble.

But reports that D.C. Mayor Muriel E. Bowser’s initial requests for additional support on Wednesday found the Pentagon flat-footed suggests Pentagon leaders were not as ready as they might have been. The National Guard now faces the task of restoring order in the city of Washington and protecting federal property. Given the urgency of this request, National Guard troops and protesters may find themselves in the middle of difficult, violent situations in the District of Columbia, and the city’s police will face the challenge of coordinating with unfamiliar units without much prior planning. If these National Guard units have not been training and preparing themselves for this type of situation over the last few months, there is a high risk of mistakes.

The slow response may also further politicize the military in the minds of some Americans, given the heavy-handed response to the largely peaceful Black Lives Matter protests in June. Military leaders likely wanted to avoid the perception that the military is involved in the U.S. election process, but this is a mission for which the National Guard is usually prepared. We will now find out if it is.

Carrie A Lee is an assistant professor at the US Air War College. Follow her on Twitter @CarrieALee1. Opinions expressed in this piece do not reflect the official position of the Department of Defense, U.S. Air Force, or Air War College.

Jim Golby, a senior fellow at the Clements Center for National Security at the University of Texas at Austin and the host of the ‘Thank You For Your Service’ podcast. Follow him on Twitter @jimgolby.