(Undated)  --  Senator Jeff Merkley is joining a bipartisan group of senators in demanding President Trump explain why he's sending more troops to the Middle East.  They're also warning him that Congress hasn't authorized military action against Iran.  The strong words are in a letter sent to the president by the Oregon Democrat along with Democrat Tim Kaine of Virginia, Republicans Mike Lee of Utah and Rand Paul of Kentucky and Independent Bernie Sanders of Vermont.  The senators wrote they're "concerned" that increasingly escalating actions by both sides will lead to what they call an unnecessary conflict between the U.S. and Iran.