In case there's anyone left with the slightest doubt, the dismissals were notably political

Cronies and cronies' cronies were appointed to the posts of the dismissed US attorneys after 2004.

The people chosen as chief federal prosecutors on a temporary or permanent basis since early 2005 include 10 senior aides to Attorney General Alberto R. Gonzales, according to an analysis of government records. Several came from the White House or other government agencies. Some lacked experience as prosecutors or had no connection to the districts in which they were sent to work, the records and biographical information show.

And no.  Not everyone does it.

Jamie S. Gorelick, deputy attorney general in the Clinton administration, said it was uncommon during her tenure to dispatch aides from Justice to become U.S. attorneys, except in urgent circumstances, such as when Robert S. Mueller III, now the FBI director, was named U.S. attorney in San Francisco to shore up that troubled office. "These jobs are serious prosecutorial jobs that require judgment and an understanding of the laws that are to be enforced," she said. "They are not meant to be steppingstones, or to give people turns at political jobs."

Dan Eggen and Amy Goldstein have the full story in the Washington Post.