Over at Reason, Jacob Sullum writes that of the three candidates seeking the presidency, only one has a record of abstaining from the practice and seeking to reform it:

On the face of it, the presumptive Republican presidential nominee, John McCain, and the two remaining contenders for the Democratic nomination, Barack Obama and Hillary Clinton, take a different view: All three supported a one-year moratorium on earmarks that the Senate recently rejected by a wide margin. But only McCain has taken a principled stand against the pet projects that legislators love to slip into spending bills.

"We Republicans came to power in 1994 to change government," McCain told the Riverside, California, Press Enterprise last year, "and the government changed us. That's why we lost the election: We began to value power over principle."
[...]
"Pork barrel spending," McCain says, "is an insult to taxpayers, a waste of public resources, and an abdication of our leaders' responsibility to be good and honorable stewards of the public treasury, for the benefit of all Americans, not just a few." He says he wants to end, not mend, earmarks, and in the meantime he declines to seek them for his own state.

Sullum also mentions Barack Obama's earmark for the University of Chicago, where Michelle Obama happens to work. I wonder why that hasn't been investigated.