This one will sink him (pardon the pun) if it gets significant airplay. This should have been the focus from the start. This focuses the disagreement squarely between the veterans and Kerry, not Kerry and Bush. Notice that nothing in this ad has anything to do with Kerry's war service itself. It focuses on what he said when he got back. I wish the swifties had never brought up anything about his service other than the fact that they did NOT commit war crimes and did NOT venture into Cambodia.
Some of them may have done so, but much later when Nixon authorized it. I found one site about the Swift Boats that indicated that some Swifts were used to transport South Vietnamese troops into Cambodia. But that was well after Kerry cut and ran. The site is http://www.pcf45.com/. It tells alot about the boats and those who served on them. It's pre cannidate Kerry, and AFAIK, has nothing about him. Click on "SEALORDS" and then in last paragraph on the resulting page on "Operation Tran Hung Dao XI" for info on ops in Cambodia starting in May of 1970, about the same time JFnK was headed to Paris to negotiate with the enemy, an action prohibited by US law. He was an inactive status Naval Reservist at the time, although that status does not make his actions any more illegal, nor is someone in that status subject to the UCMJ. (mores the pity).