In November, six Democratic lawmakers recorded a video directed at members of the US military and intelligence agencies. In it, they issued a blunt reminder:

"The laws are clear: […] You must refuse illegal orders."

The lawmakers were issuing the warning against the backdrop of US airstrikes on boats off the coast of Latin America the Trump administration claims are suspected drug runners. Many Democrats and legal experts, however, argue these strikes are illegal.

Since returning to office, Trump has successfully expanded his power over his own party, the courts and the American people. Now, like many autocrats around the world, he’s trying to exert control over the military.

The list of people Donald Trump has punished or threatened to punish since returning to office is long. It includes the likes of James Comey, Letitia James, John Bolton, as well as members of the opposition, such as Adam Schiff, Mark Kelly and Kamala Harris.

In fact, he has gone so far as to call Democrats "the enemy from within", saying they are more dangerous than US adversaries like Russia and China.

According to Lucan Way, a professor of democracy at the University of Toronto, when a leader attacks the opposition like this, it's a clear sign a country is slipping into authoritarianism.

In democratic systems, the courts are a vital check on a leader’s power. They have the ability to overturn laws and, in Donald Trump’s case, the executive orders he has relied on to achieve his goals.

Since taking office, Trump has targeted the judiciary with a vengeance. He has attacked what he has called "radical left judges" and is accused of ignoring or evading court orders.

The Supreme Court has already handed the Trump administration some key wins in his second term. But several cases now before the court will be pivotal in determining how much power Trump is able to accrue – and what he'll be able to do with it.