in December 1953. President Beck initially refused to sign the agreement, and threatened to take the Teamsters out of the AFL if forced to adhere to it. Three months after the pact was signed, the Teamsters agreed to submit to the terms of the no-raid agreement. Shortly thereafter, the AFL adopted Article 20 of its constitution, which prevented its member unions from raiding one another. The union's affection for raiding led it to initially oppose the AFL–CIO merger in January 1955, but it quickly reversed itself. Rise, fall, and disappearance of Jimmy Hoffa Hoffa achieved his goal of unifying all freight drivers under a single collective bargaining agreement, the National Master Freight Agreement, in 1964. Hoffa used the grievance procedures of the agreement, which authorized selective strikes against particular employers, to police the agreement or, if Hoffa thought that it served the union's interest, to drive marginal employers out of the industry. The union won substantial gains for its members, fostering a nostalgic image of the Hoffa era as the golden age for Teamster drivers. Hoffa also succeeded where Tobin had failed, concentrating power at the international level, dominating the conferences which Beck and Dobbs had helped build. In addition, Hoffa was instrumental in using the assets of the Teamsters' pension plans, particularly the Central States plan, to support Mafia projects, such as the development of Las Vegas in the 1950s and 1960s. Pension funds were loaned to finance Las Vegas casinos such as the Stardust Resort & Casino, the Fremont Hotel & Casino, the Desert Inn, the Dunes hotel and casino (which was controlled by Hoffa's attorney, Morris Shenker), the Four Queens, the Aladdin Hotel & Casino, Circus Circus, and Caesars Palace. The pension fund also made a number of loans to associates and relatives of high-ranking Teamster officials. A close associate of Hoffa during this period was Allen Dorfman. Dorfman owned an insurance agency that provided insurance claims processing to the Teamsters' union, and which was the subject of an investigation by the McClellan Committee. Dorfman also had increasing influence over loans made by the Teamsters' pension fund, and after Hoffa went to prison in 1967, Dorfman had primary control over the fund. Dorfman was murdered in January 1983, shortly after his conviction, along with Teamsters' president Roy Lee Williams, in a bribery case. Hoffa was, moreover, defiantly unwilling to reform the union or limit his own power