Why are tax cuts considered "spending" for Democrats, but not for Republicans?

About $326 billion of the $787 billion cost of the stimulus is from tax cuts through the year 2010, according to this report a href="http://www.house.gov/jct/x-19-09.pdf" rel="nofollow"http://www.house.gov/jct/x-19-09.pdf/a by Congress' Joint Committee on Taxation. That is not generally considered "spending" — especially not to Republicans and all the tax cuts they gave to the rich from 2001 to 2009. Why weren't Bush's tax cuts recorded as "spending"?