These are tough times for ex-politicians. Under pressure to trim their own perks, members of Congress are cracking down on retirees. The House has voted to stop paying for clerical staff both for former Speakers and retired Presidents after five years out of office. The Senate is expected to take up the provisions in July. Meanwhile, former President Bush says he'll return $50,000 in office support to the Republican National Committee. The stipend, first disclosed by this magazine (BW--June 28), was supposed to cover expenses incurred while promoting GOP causes. But as Party Chairman Haley Barbour now admits: "So far, he really hasn't done anything."