The United States will no longer mediate peace negotiations between Ukraine and Russia after Vladimir Putin refused to sign up to a ceasefire.The State Department said it is changing “the methodology of how we contribute” to the talks and will no longer “fly around the world at the drop of a hat” for meetings. “We will continue to help, but we will no longer fly around the world as mediators in meetings,” said Tammy Bruce, a spokesperson.She added that Kyiv and Moscow must now present “concrete” proposals for ending the war and should meet directly to resolve the conflict.Washington withdrawing...