WASHINGTON (AP) — Joe Biden’s presidency is entering a new and more perilous phase. He’s past the 100-day mark in office, and he’ll have to overcome stiffer Republican opposition to his agenda and keep Democrats united as he pushes for $4 trillion on programs that have echoes of the New Deal and the Great Society. Biden is racing against the calendar while governing with the most slender of congressional majorities. He knows that historically the party in the White House loses seats in midterm elections, and that could happen in 2022. His next 100 days will feature his first foreign trip but will be dominated by efforts to pass his proposals on infrastructure and children, families and education.