“No person shall…hold any office, civil or military, under the United States…”
Let’s let the Constitution clear this up, once and for all:
Amendment XIV [14th]
“No person shall be a Senator or Representative in Congress, or elector of President and Vice President, or hold any office, civil or military, under the United States, or under any state, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any state legislature, or as an executive or judicial officer of any state, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof. But Congress may by a vote of two-thirds of each House, remove such disability.”
“The Congress shall have power to enforce, by appropriate legislation, the provisions of this article.”
Clearly written; Congress has the power, by simple majority of each House, to disqualify the president or any civil or military office holder in America who has engaged in insurrection or rebellion against the government from ever holding office again. Furthermore, Congress requires a two-thirds super majority of each House to reverse such a decision.
A simple majority of Congress is all that it takes.
[The 14th Amendment differs from the constitutional instructions on impeachment and removal which require a two-thirds majority for conviction and judgement. See US Constitution; Article I Section 3 Clause 6 and 7; Article II Section 4.]