Major cases coming before the Supreme Court will force the justices to consider the extent of President Donald Trump’s power. Today, the high court will hear oral arguments in Trump v. Slaughter, which will determine whether a president has the authority to reshape independent federal agencies. And over the weekend, the justices indicated that they would take up the landmark case on birthright citizenship. Playbook’s Jack Blanchard and White House reporter Megan Messerly walk through what to know ahead of the day’s proceedings, plus what Trump said about the Ukraine peace negotiations.