21.   But approval is by no means certain, particularly because the plan would require the city to forgo anticipated tax revenues at a time it faces major budget gaps.

22.   Bush has said in all the debates that his plan would require people at upper-income levels to pay a greater share of federal income taxes.

23.   But because the plan would require the state to provide training programs or public-sector jobs to welfare recipients, it might not save the state any money.

24.   But even the best-laid plans required improvisation.

25.   But he said that any plan would require the approval of the city and the New York State Bureau of Military and Naval Affairs.

26.   But implementing even the scaled-back preservation plans will require getting the Mulberry Grove property from the ports authority.

27.   But the plan requires the approval of the City Council, whose Speaker, Peter F. Vallone, wants to put the stadium issue to a public vote.

28.   But the more controversial measures, such as arming pilots, would take longer to implement because of the training that such a plan would require.

29.   But the plans require grants of immunity from antitrust rules that so far they have not gotten.

30.   But the plan would require the Teamsters to break from their longstanding tradition of pooling pension benefits from multiple employers and providing benefits uniformly to retirees.