Bush's promise to cut taxes was the centerpiece of his 2000 presidential campaign, and upon taking office, he made tax cuts his first major legislative priority. A budget surplus had developed during the Bill Clinton administration, and with the Federal Reserve chairman Alan Greenspan's support, Bush argued that the best use of the surplus was to lower taxes. By the time Bush took office, reduced economic growth had led to less robust federal budgetary projections, but Bush maintained that tax cuts were necessary to boost economic growth. After Treasury secretary Paul O'Neill expressed concerns over the tax cut's size and the possibility of future deficits, Vice President Cheney took charge of writing the bill, which the administration proposed to Congress in March 2001.