Only a Democrat could think you could zero out DOD, then go out and buy defense capability when and if you need it.
New modern aircraft type? Bare minimum of ten years from concept to proof of prototype, likely five years more to squadron service.
New warship type? More like 15 to launch the hull, absolute minimum of at least another two for fitting out and trials.
Army and Marine troop and leader training establishments, core unit structures, and commissioned/noncommissioned unit leadership manning and structures? It would take a full lifetime to replace them from nothing.
You cannot rent the kind of tradition and honor that make men face death rather than turn tail and run.