The vote, which was seen as a test of the President's authority, was hailed as opening the possibility of further bipartisan co-operation in Congress.
In the week between the announcement of the Senate debate on the chemical weapons convention and the actual debate, Mr Clinton made elaborate efforts to justify US accession to the treaty and meet some objections raised by its opponents. His final gambit was to write to the wavering Senate Republican leader, Trent Lott, promising that if the treaty turned out to be contrary to US security interests, or to foster rather than stem proliferation of chemical weapons, he would withdraw the United States from the treaty.
That promise convinced Mr Lott to drop most of his objections. The vote was 74 to 26, a majority of four more than the two-thirds that was required.
Earlier, Mr Clinton had assembled senior military and political figures to defend the treaty from the security and foreign policy perspectives. On Thursday morning, half way through the debate, the Senate went into a rare closed session to hear information about intelligence considerations.
The ground had additionally been prepared by the Secretary of State, Madeleine Albright, who travelled the US, trying to win over sceptical senators and public opinion.
Republican opponents of the treaty, such as Mr Lott, praised Mr Clinton for agreeing to toughen the resolution that accompanied the text of the treaty. Afterwards, they were able to claim it was these assurances of safeguards for US security that had convinced them. Others, however, noted that the resolution was a secondary document and that if any conflict arose in future between the treaty text and the resolution, the treaty text would be the one considered legally binding.
For both Democrats and Republicans, the Senate vote held the hope that the budget, which is the subject of much behind-the-scenes bargaining, might be agreed without the acrimony and stalemate that have marked the process in the past.