The Treasury Department is seen near sunset in Washington, Wednesday, Jan. 18, 2023. The Treasury Department projects that the federal government on Thursday will reach its legal borrowing capacity, an artificially imposed cap that lawmakers have increased roughly 80 times since the 1960s. Markets so far remain calm, as the government can temporarily rely on accounting tweaks to stay open. (AP Photo/Jon Elswick)

WASHINGTON (AP) — The Treasury Department says it has started taking “extraordinary measures” as the government has run up against its legal borrowing capacity of $31.381 trillion. Treasury Secretary Janet Yellen sent a letter to congressional leaders Thursday urging them to act to raise the debt limit. Frictions between President Joe Biden and House Republicans are raising alarms about whether the U.S. can sidestep a potential economic crisis. Markets so far remain calm, as the government can temporarily rely on accounting tweaks to stay open. That means any threats to the economy are several months away. But this particular moment seems more fraught than past brushes with the debt limit.