ADDED: LBJ->Nixon cannot be used to judge this due the the was in Vietnam (and to a lesser extent that might hold true for W after 9/11, and he showed his usual "genius" in picking NASA leadership), Nixon/Ford->Carter, though, would bear investigation. And Carter was absolute, total death to anything nuclear, it's just like him to take a small minded view of his experiences in cleaning up this mess: https://en.wikipedia.org/wiki/Chalk_River_Laboratories#1952_... And, hmmm, this official NASA history says "Jimmy Carter was perhaps the least supportive of U.S. human space efforts of any president in the last half-century...." http://www.nasa.gov/50th/50th_magazine/10presidents.html

Obama might be an exception, though, and I'm pretty sure that's true for space. He's not from the same generation as the bulk of those cultural anti-science Baby Boomer, about my age, in fact, was I'd guess wowed by the Apollo program like I was. Would have to check for his support of science research, though.

I witnessed this first hand when Clinton NASA cutbacks killed the space technologies etc. company I started working at in late 1993, (ADDED:) and they're mentioned in the above NASA history link in the added paragraph above. And of course the cancellation of the already being built Superconducting Supercollider had much more than direct effects, which included a line running outside the MIT EECS Undergraduate Office of students transferring into the department.

Which party would be more interested in keeping defense contractors in business?

Hard to win, impossible nowadays against a serious opponent, if you've let them go out of business. And many many of our troops needlessly died in WWII due to our playing catch up because we'd neglected these "merchants of death".

Also goes for defense related research, etc.; our response to that is not 1 ton ANFO IEDs (https://en.wikipedia.org/wiki/Sterling_Hall_bombing).

The Romans had it right, "si vis pacem, para bellum" (https://en.wikipedia.org/wiki/Si_vis_pacem,_para_bellum).