Frigid January weather prompted Donald Trump's second inauguration to be held in the rotunda of the US Capitol, an iconic room ringed by busts of former presidents that lies at the heart of Congress. Almost immediately after departing the Capitol, Trump took aim at the legislative branch, moving to siphon from lawmakers the powers to control spending, agencies and declaring war, and take them for himself, experts say. "What we have seen over the past year represents a real escalation by the executive branch of its intrusion into things that are historically powers of Congress," said Molly Reynolds, the director of governance studies at the non-partisan Brookings Institution.