For the first time in the campaign, the two democrats competing for their party’s next presidential nomination will share the same stage in Iowa — tonight in Des Moines. Bill Bradley and Al Gore will deliver separate speeches to Iowa democrats at tonight’s “Jefferson/Jackson Day” dinner. Gore will use his speech to outline the general themes of his campaign, like education reforms and preservation of Social Security and Medicare. Gore has moved his national campaign headquarters out of Washington, D.C. to Nashville and shaken up staff — but he plans no shake-up in Iowa. Bill Bradley’s staff refused to let reporters question the candidate yesterday.