The assumption was that, because national security is apparently less of a priority for Democrats, the GOP would ultimately cave and agree to raise taxes in order to avoid the sequester, half of which would come from the defense budget. That is why the White House was somewhat baffled during the fiscal-cliff negotiations when House Speaker John Boehner (R., Ohio) did not come to the table with an alternative to the sequester, specifically the defense portion.
Obama ultimately got $600 billion in new revenue as part of that final deal, in the form of rate hikes on wealthy earners. Now, he’s insisting on more, and has said he will oppose any effort to replace the sequester that does not involve further tax increases. Unfortunately for him, Republicans appear willing to let the sequester take effect, and insist that any effort to raise taxes is “dead on arrival.”