It's insignificant--unless it means people vote for you or against you because of your former military status.
It's part of the picture of the candidate. Vietnam: Cheney got deferred. Gore had a non-combatant commission. Bush served in the Air National Guard (something like the old RAF Auxiliary squadrons, just to cop a very broad analogy) and did not see combat. Clinton avoided military service. Schwartzenegger was in Austria, and then doing muscle beach stuff in America. Edwards was too young to be subject to the draft, and didn't enter the military. There's a lot of other things that are part of the respective pictures--Kerry's post-combat protest agains the Vietnam War, Cheney's long-term connections with Halliburton, Edwards' medical malpractice litigation, Clinton's bimbo eruptions, Bush's alleged drug and alcohol abuse, and everything else from giving CPR to a hamster to landing on an aircraft carrier and saying "mission accomplished."
The problem is that older men make saner decisions for the most part, which do not adapt well to to 30-second attack ads. You might actually have to talk about issues.
Mark Schynert