By AAMER MADHANI
WILMINGTON, Del. (AP) — The White House says President Joe Biden has conferred with Ukraine’s leader over the Russian troop buildup near its border, promising that the U.S. and allies will act “decisively” if Russia further invades Ukraine. Biden and President Volodymyr Zelenskyy’s on Sunday came as the U.S. and Western allies prepare for a series of diplomatic meetings to try to de-escalate a crisis that Moscow says could rupture ties with Washington. White House press secretary Jen Psaki says Biden underscored his commitment to the principle of “nothing about you without you,” the tenet that that it won’t negotiate policy that impacts Europe without its allies’ input.