Which agency is the better one to jain Homeland security or NCIS? .....?

....(Also for thoes whos worked for NCIS what type of civilian cases are NCIS agents allowed to work and what task forces are they on?) I was hoping to be an NCIS agent in the future but after all the crap the Pentagon nut jobs is doing trying to take away the 1st Amendment from Sailors not letting them have a Confederate flag but it's okay with them having gay flags and probably even Isis flags for all they care.....(doesn't really look very promising anymore:/)so I started looking into Homeland Security, a lot of people say they're like a military branch of Their Own also one of my dreams is to be able to be the one that brings down crooked senators and congressmen City Mayors and so forth (crooked politicians) and then move down to terrorist organizations & big crime Lourdes, gang Bangerz and stuff that pretty well rule over cities the people that these politicians are paying to do all the destruction. so my question is which agencies better and which one would I be more suited to be able to arrest people like the Illinois house Speaker Mike Madigan who is in fact under investigation for corruption and sexual assault? .....