The clear intent of this provision [Logan Act] is to prohibit unauthorized persons from intervening in disputes between the United States and foreign governments. Nothing in section 953 [Logan Act], however, would appear to restrict members of the Congress from engaging in discussions with foreign officials in pursuance of their legislative duties under the Constitution. In the case of Senators McGovern and Sparkman the executive branch, although it did not in any way encourage the Senators to go to Cuba, was fully informed of the nature and purpose of their visit, and had validated their passports for travel to that country
Did they fully inform of the nature of their visit? Why assume that?