President-elect Donald Trump is considering Keith Kellogg, a retired lieutenant general who has presented him with a plan to end the war in Ukraine, to serve as a special envoy for the conflict, according to three sources with knowledge of the matter. Kellogg, who was the chief of staff for the White House National Security Council during Trump's 2017-2021 term and national security adviser to then-Vice President Mike Pence, would likely play a central role in attempting to resolve the conflict if he is selected. Kellogg's plan for ending the war, which began when Russia invaded Ukrainian sovereign territory, involves...