This discussion reminds me of what happened when we were told to war game the defense of the Philippines during one of our advance classes. One of my classmates had split the US and Philippine units into two. He sent what was essentially a bared down Northern Luzon Force to hold the mountains in the north to act as an organized stay behind force to constantly harass Japanese units that were coming down from the north. The other half he sent immediately to Bataan according to the war plan.

The northen unit was able to impede Japanese progress enough and was able to live off the land by having a friendly population to operate from. With that force acting as a speed bump, units in Bataan were given more time to consolidate their defenses and be better prepared. Even with the isolation of the Philippines from US mainland supply, by organizing irregular units to constantly harass Japanese units rear areas, he managed to prevent the Japanese from concentrating enough forces to make a heavy push into Bataan. And with conventional units still existing to support the irregulars, it was the invading Japanese who found themselves surrounded, their mobility severely restricted. He didn't repulse the Japanese but he was able to contain them, thus giving time for whatever reinforcements from the US mainland to organize properly and get through. This, he explained to our somewhat amused tactical officer/instructor, was the essence of the War Plan. This guy's moves and canny planning extended the time line of the defense of the PI and Bataan by at least five months after the historical April surrender until our TACO called it a day.

He essentially combined irregular and conventional tactics. All of us (including me) who used only conventional tactics for the period lost. That very wily guy is now working as a geologist for Shell.