Pres. Clinton plans to stand tough this year against congressional Republicans who have attached at least 39 anti-environmental riders to government spending bills. In past years, Clinton has caved in and approved bills containing such riders, but the administration is now signaling that he is ready to veto major appropriations bills if the riders aren’t removed. Al Gore’s presidential hopes seem to be partially responsible for the administration’s harder stance. Gore wants to show his eco-friendly stripes, particularly after Friends of the Earth earlier this month endorsed his Democratic rival, Bill Bradley.