THE WORD OUT OF WASHINGTON IS that President Reagan and the Republican Party may have lost control of the Senate for 1987-88 in last week's election, but the president gained a scapegoat - a Democrat-controlled Senate.

But for all their new power, the congressional Democrats will have to reconcile themselves to the idea that sending the president legislation like the highly protectionist omnibus trade bill passed by the last House will only lead to a veto - and probably a veto that can't be overridden. On the other hand, the president will have to abandon the standoffish position he took through most of the later Senate effort to produce a bipartisan alternative to the House measure.