As press secretary Jay Carney put it:
"The salary for the President, as with Members of Congress, is set by law and cannot be changed. However, the President has decided that to share in the sacrifice being made by public servants across the federal government that are affected by the sequester, he will contribute a portion of his salary back to the Treasury."Deputy Defense Secretary Ash Carter and Congresswoman Tammy Duckworth have also followed suit, as has Alaska Sen. Mark Begich.
We don't seem to be anywhere near the end game of the congressional Republicans' demand that the federal budget be balanced via ongoing tantrum, but having members of the administration and other Democrats come out in support for federal workers in this manner seems a creditable thing. No doubt all Republican members of Congress will be chipping in as well, since they're the ones demanding the cuts.