US President Donald Trump's deployment of National Guard troops in Democratic-led cities, against the will of local officials, is facing two key legal tests on Thursday.
Court hearings are set to begin in Portland, Oregon, and Chicago, Illinois, where local leaders have sued the government alleging the use of US military on civilian streets is unconstitutional.
The White House has defended the deployments, with Press Secretary Karoline Leavitt saying "we're very confident in the president's legal authority to do this".
Trump has previously sent the National Guard to Los Angeles and Washington DC, arguing the troops were needed to crack down on illegal immigration and crime.
The president has also said the National Guard troops are necessary to protect federal immigration officers carrying out deportation operations.
In Portland, protests outside of an Immigration and Customs Enforcement (ICE) building have grown increasingly tense, described by some local residents as a "war zone".
After Trump directed the deployment of 200 members of the Oregon National Guard in September, a judge temporarily blocked the manoeuvre. And when Trump subsequently threatened to send National Guard members in from another state, the judge expanded the court's order to block this too.
A three-judge panel on the Ninth Circuit Court of Appeals will hear arguments on Thursday about whether to lift the lower court's order temporarily blocking the use of Oregon's National Guard.
"The Trump administration is committed to restoring law and order in American cities that are plagued by violence due to Democrat mismanagement," White House spokeswoman Abigail Jackson said in a statement Wednesday, according to NBC News.
"And President Trump will not stand by while violent rioters attack federal law enforcement officers."
Oregon Governor Tina Kotek, a Democrat, said "there is no insurrection in Portland, no threat to national security".
US District Court Judge April Perry will also hear arguments on Thursday about the government's attempt to deploy National Guard troops to Chicago, Illinois.
The city has been a particular flashpoint in the Trump administration's effort to detain and deport undocumented migrants, with reports of federal agents descending from Black Hawk helicopters during an immigration raid and using chemical irritants on non-violent protesters.
One woman was shot by a federal agent during a protest in the city. Hundreds of Texas National Guard troops have since arrived in the area.
The lawsuit by Illinois officials argues that the Trump administration's efforts are not only illegal, but also an attempt to manufacture a crisis by stirring civil unrest.
Chicago Mayor Brandon Johnson told BBC News that "handpicking National Guard people from another state, the state of Texas, and then sending them to the state of Illinois - this is illegal, unconstitutional, and dangerous".
