Should Soldiers in MI and CID be forced to take a poly?

LTC (Join to see) Yes, absolutely. It is strictly an administrative polygraph from which to base an opinion on a person's trustworthiness to hold certain security clearances/access. It is not a "lifestyle" polygraph and has very targeted questions geared strictly at trustworthiness.

I have undergone quite a few of those polygraphs since retiring because of my civilian occupation (primarily when I was assigned to manage para-military security forces for the DOE/National Nuclear Security Administration nuclear weapons complex research, testing, manufacturing, and storage facilities/installations).

Hillary Clinton would never be able to pass one ... Trust me on that one.

I'm going to say yes. While not "admissible" in a court of law, the poly is a valuable tool in any CI/CID investigation. Also, if you are be assigned to a national level agency (CIA, NSA, etc) as a military intelligence service member, you will be required to take a poly. One last thing...doing the most recent wars, one of the biggest headaches military MI leaders had with getting support from national agencies was the fact that almost all tactical service members (I keep using that term because it applies to the joint nature intelligence work had become during the war and I suspect will continue to be) didn't have polygraphs and national agencies required it for their workforce (they didn't want a two-tier security system).

I can see view points from either side of the discussion, but for my opinion I would think that it should be put to use as they are privileged with special information.