The Vandenberg Resolution () was passed in June 1948 and was proposed by and named after US Senator Arthur Vandenberg. Negotiations over the nature and degree of commitment by the United States to defend its North Atlantic allies were complicated by the conflicting desire of the allies for an iron-clad assurance of immediate US intervention in case of a Soviet attack and the insistence for the US Senate that its constitutional prerogatives to be preserved, especially the power to commit the US to war. US State Department officials, after assuming a common position of support for the idea of a treaty, patiently wove together a text that balanced the concerns of its European allies, the Senate, and the US military. Domestic US politics, particularly those arising from the presidential election of 1948, played an important role in the international and congressional negotiations. In keeping with practices worked out during the congressional debate over the Marshall Plan, discussions between administration and Republican leaders over collective security arrangements in Europe were held between April and June 1948. The talks reflected the likelihood of a Republican (GOP) presidential victory in the November elections. Republican Senator Arthur H. Vandenberg, Chairman of the Senate Foreign Relations Committee and President pro tempore of the Senate, was a leading candidate for the Republican presidential nomination before he dropped out of the contest. In friendly and candid talks with Secretary of State George Marshall and Under-Secretary Robert A. Lovett, Vandenberg embraced the concept of a North Atlantic alliance and agreed to support it in the Senate only if substantive negotiations were delayed until after the elections, and the UN Charter was more clearly affirmed and invoked in the prospective treaty. The role of personal relations in foreign policy was demonstrated by Lovett's informal discussions with Vandenberg, who was now a convinced internationalist and wanted to be helpful but was mindful of political realities, which he sought to impress on the Lovett and the Truman administration. In an April 11 meeting, Lovett tactfully probed Vandenberg's thinking on a number of key issues, including the type of aid Congress would approve; the form of a pact, particularly the willingness of the Senate to approve a slightly-modified version of the Rio Treaty with regard to Europe; the role of the United Nations in collective security arrangements; and the legislative preparation needed for eventual conclusion of a long-term European security agreement. A