As tensions grow between demonstrators and the White House's immigration policies, questions may arise over the president's ability to deploy the National Guard.

Who controls the National Guard? The National Guard is a hybrid entity that serves both state and federal interests and often operates under state command and control, using state funding.

Sometimes, troops will be assigned by their state to serve federal missions, remaining under state command but using federal funding.

Generally, federal military forces are not allowed to carry out civilian law enforcement duties against U.S. citizens except in times of emergency.

When can the National Guard be deployed? An 18th-century wartime law called the Insurrection Act is the main legal mechanism that a president can use to activate the military or National Guard during times of rebellion or unrest. But President Donald Trump didn’t invoke the Insurrection Act on Saturday when deploying the National Guard to Los Angeles.

What about the National Guard in Texas? Back in February, Gov. Greg Abbott gave Texas Guard members authority to arrest and detain people for entering the U.S. illegally from Mexico under an agreement with the Trump administration that expands the military’s role in immigration enforcement.