While I have no insider information, the key decision on the Surge was not if, but when.

Bush had long asserted that the US would stand down when the Iraqis stood up. Surging extra troops into Iraqi would have been premature until the Iraqis had a creditable army and a cohesive government willing and able to command it. Once the Iraqis were ready to roll and to hold the reclaimed territory, THEN it was time for us to commit our reserves to a final flushout of A-Q. The two elements of extra US troops AND real Iraqi governance made the Surge work. Prior to that, the US was just keeping a lid on things and attriting fanatical young Muslim fighters.

I think McCain understood this program/timeline and was able to get ahead of it politically and use it to his advantage. A few months before the Surge was ready to roll, he started demanding it publicly, thereby taking credit for prescience and great stategic accuman.

Programmer – your encouragement to work on military R&D by bright young engineers rings true. At the last place I worked, the brightest guy had worked on the human sniffer program for the Viet Nam war. The idea was a machine that could smell humans and so warn our troops when the NVA or VC were hidding in the bushes. He even took it to the field for testing. Today, he is designing the computerized controls for new nuclear power plants.