If many conservatives are liberals who have been mugged by reality, Brooks, a registered independent, is, as a reviewer of his book said, a social scientist who has been mugged by data. They include these findings:
Obama Releases 2000-2006 Tax Returns
What is surprising, given the recent controversy over Obama's membership in the Trinity United Church of Christ, is how little the Obamas apparently gave to charity -- well short of the biblical 10% tithe for all seven years. In two of the years, the Obamas gave far less than 1% of their income to charity; in three of the years, they gave around 1% of their income to charity. Only in the last two years have they given substantially more as their income skyrocketed -- 4.7% in 2005 and 6.1% in 2006.
(Of course, it is possible that the Obamas may have made gifts to other worthy causes that were not deductible for federal income tax purposes.)
The difference may lie in that conservatives tend to feel compelled to give directly. Liberals see the cause as yet another role for the government to fulfil...by taking money from those that already give more as it is.