More than 2,000 Marines from Camp Lejeune have arrived in the Adriatic Sea, and now await adecision by the Clinton Administration on whether to send them into Bosnia. The White House said it "would not rule out" ground action to release the nearly 400 UN hostages currently held by Bosnian Serb forces. ButTIME Pentagon correspondent Mark Thompsonsays sending the 24th Marine Amphibious Expeditionary Unit after the hostages is highly unlikely. "In the first place, it's an amazingly difficult mission to expect these Marines to find 400 people in these mountains where the Serbs have lived for hundreds of years." More important, according to Thompson, is that sending in the Marines would likely be unpopular at home.Senator Richard Lugar (R-Ind.), a presidential hopeful, today cautioned President Clinton to seek Congressional approval before deploying any troops. ButSenate Majority leader Bob Dole said he supports intervention, saying it is time for the U.S. to follow through on its commitments in Bosnia. Maybe so, but as Thompson notes: "Clinton so far has not made the case that this passes the 'mother test,' that is, he can't go to the mother of some Marine and tell her her son did not die in vain."