One Trustee's refusal to act will jeopardize the qualified status of the plan. I think the other Trustee has an obligation to act to protect the participants, regardless of what the plan and/or trust documents say.
QUOTE
Act Sec. 404.(a)(1)
PRUDENT MAN STANDARD OF CARE. --Subject to sections 403(c) and (d), 4042, and 4044, a fiduciary shall discharge his duties with respect to a plan solely in the interest of the participants and beneficiaries and --
(A) for the exclusive purpose of:
(i) providing benefits to participants and their beneficiaries; and
(ii) defraying reasonable expenses of administering the plan;
(B) with the care, skill, prudence, and diligence under the circumstances then prevailing that a prudent man acting in a like capacity and familiar with such matters would use in the conduct of an enterprise of a like character and with like aims;
(C) by diversifying the investments of the plan so as to minimize the risk of large losses, unless under the circumstances it is clearly prudent not to do so; and
(D) in accordance with the documents and instruments governing the plan insofar as such documents and instruments are consistent with the provisions of this title and Title IV.