The anniversary of the Jan. 6 riot arrives this week with the congressional committee investigating the attack confronting a series of difficult questions, including how forcefully to flex its subpoena power and whether the Supreme Court will stymie a major element of its inquiry.

As the nine-member panel continues to examine the events leading up to the worst attack on Congress in centuries, it is waiting to see whether the Supreme Court will refuse a request from former President Donald Trump to block the committee’s access to White House records related to the riot. The committee also has not ruled out moving to subpoena members of Congress, or Trump and former Vice President Mike Pence.

Thursday will mark a year since a mob of Trump supporters stormed the building, determined to disrupt the formal certification of President Joe Biden’s electoral victory. At least seven people died in connection with the riot, dozens more were injured and hundreds of workers in the Capitol were shaken and traumatized, further fracturing an increasingly partisan Congress.