Obama budget’s boost for military spending points to brewing national security debate

The battle over the budget that President Obama will submit Monday is emerging as a preview of the 2016 presidential election debate on national security, an area that for now appears to be the greatest vulnerability of Obama and the Democrats.

The president will ask Congress to break through its own spending caps — commonly referred to as “sequestration” — and allocate about $561 billion for Pentagon expenditures, about $38 billion more than is currently allowed under the law.

There’s broad consensus in both parties that the military needs more...