Roughly an hour after two bombs exploded near the finish line of the Boston Marathon, resulting in dozens of casualties and at least two fatalities, New York Times columnist Nicholas Kristof used the tragedy to blame Republicans for blocking acting ATF director B. Todd Jones, Obama's choice for director of the Bureau of Alcohol, Tobacco and Firearms.
A post on his Twitter feed  (since deleted) linked to an old Washington Post story on a Republican political maneuver.
explosion is a reminder that ATF needs a director. Shame on Senate Republicans for blocking apptment articles.washingtonpost.com/2013-02-01/wor… 
— Nicholas Kristof (@NickKristof) April 15, 2013
About half an hour later Kristof took back his original tweet : "People jumping on me for criticizing Sen Repubs for blocking ATF appointments. ok, that was low blow. i take it back."
Kristof's offensive, politically motivated tweet is remindful of Times columnist Paul Krugman's post two hours after the shooting of Rep. Gabrielle Giffords, accusing the shooter (before he was even named) of being motivated by conservative politics .