You shouldn't need a 3:1 ratio. All you need is better tactics.
hm.. i dont know how many of you were on some millitary training or school but 3:1 ratio is a common thing.
and it counts in terms of equal armies, eg. to conquer one fortified US division you'll need a strength of 3 equal divisions, ofcourse you can try with 1:1 but to make certain of victory 3:1 ratio is minimum.
If someone remembers recent war in Croatia serbs couldnt conquer tovn of Vukovar for months even with forces way more that 3:1 ratio, that's what im talking about.
thats the basics, ofcourse with current modern weaponery that is not the case (someone mantioned afganistan...?) couse one button nuke settles things down.