We must also realise that Kerry may purposely be encouraging these vets using the issue as a smoke screen to his flip-flops on the issues, his bad voting record...etc. Though I tend to believe the Vets over Kerry there may be a chance that Kerry's records may appear to prove this group is not being truthful. Kerry's military records may be his october surprise thus making Bush look bad (even though Bush is not behind it).
Best for Bush and republicans to continue to pin Kerry on his record in the Senate. The Swift Boat Veterans are doing just fine going against Kerry all by themselves. We, as citizens, can also support swift boat veterans by helping them get their story in mainstream media.
IMO, Bush should only address it if asked directly. Then, he should say that he does not know where the truth lies and therefore has no position on the matter. He is more concerned with Kerry's performance and positions as a senator since then.