"Conservative think tanks like the Heritage Foundation and Cato Institute have criticized Bush for his big increases in spending, which far exceed those of the Clinton era"

This quote suggests that conservative think tanks, such as the Heritage Foundation and Cato Institute, are not in favor of the Bush administration's spending policies. They have actually slammed Bush for his large increases in costs, which are much higher than those of the Clinton age. This might be viewed as a sign of displeasure from the conservative side of the political spectrum, as they are traditionally more fiscally conservative and advocate for smaller sized federal government and lower costs. The criticism from these think tanks could be seen as an indication that Bush's costs policies are not in line with their perfects. It could also be seen as a sign that the Bush administration is not being fiscally accountable with the nation's money.