WASHINGTON (AP) — The four Democratic senators seeking the White House want to be out there campaigning, but they're pulled off the presidential campaign trail and into the Senate to serve as jurors in President Donald Trump's impeachment trial.

That means forgoing raucous events and adoring crowds for hours of passively listening to a procedure designed to be solemn and rule-bound. The presidential hopefuls can't freely ask questions or even talk to their colleagues or use their cellphones. It amounts to a political muzzle for Sens. Elizabeth Warren of Massachusetts, Bernie Sanders of Vermont...