Would they? Labours recent defence strategy was no worse and I'd suggest better than the Tories. After all, it was the labour government that ordered the aircraft carriers for example. The Tories scrapped the Harrier, Nimrod, Hercules about to be, reduced flying training fleets, have closed down numerous bases, reduced main battle tank fleets, shrunk the armed forces significantly, just a few that spring to mind.
That said, I'm not convinced by either of the main parties defence strategy.......... always seems to be a target for saving and budget reduction under s mythical SDR that alleges new equipment and technology will be funder as a result, but never is.