FCC Commissioners Jonathan Adelstein, a Democrat, and Robert McDowell, a Republican, are considered swing votes. McDowell's office confirmed that the regulator is "undecided," while Adelstein's office was not immediately available for comment.

Sources said the lack of a third vote explains why action that Tate said in early October was imminent has not occurred.

In May, the Federal-State Joint Board on Universal Service headed by Tate recommended that the agency cap money being awarded to so-called competitive carriers, mostly wireless companies, with the goal of curtailing the fund's size while a comprehensive overhaul is pursued.

Supporters blame mobile telephone companies that have been receiving subsidies for a billion-dollar increase in the fund's growth in recent years. The wireless association CTIA counters that its industry is being unfairly singled out and that a cap is illogical given that its members are well-positioned to reach rural areas.

In June, the proposal was panned at a hearing by Senate Commerce members from both parties representing largely rural states. The panel also has tentatively scheduled a Dec. 13 FCC oversight hearing. Sources were divided on whether Martin, a Republican, would wait until after Congress adjourns for the year to announce a temporary cap, assuming he garners the votes, to avoid any backlash.

Despite the criticism, Martin has seized the opportunity presented by a spate of wireless industry mergers to impose interim caps on major carriers. Sources said the tactic has effectively forced major players to accept the restriction as a condition for getting their deals approved.

Last month, the agency imposed the restriction on the buyout of Alltel by TPG Capital and the Goldman Sachs Group, a deal that closed Friday. The FCC took the same action Thursday in its approval of AT&T's acquisition of Dobson Communications.

"Via merger conditions, the FCC has already capped, or is likely to cap, about half the current" funding for competitive carriers, Anna-Maria Kovacs, president of Regulatory Source Associates, concluded in a policy analysis. The FCC also is expected to impose USF thresholds on the pending merger of Verizon Wireless and Rural Cellular Corp., and on T-Mobile's acquisition of Suncom Wireless.

The moves could make an industry-wide cap more palatable to Congress by enabling it to be presented as an extension of restrictions that apply elsewhere, industry watchers said. "It's amazing how much you can accomplish if you use every tool to get there," a source said, adding, "You can't undersell the chairman."

Meanwhile, the joint board has issued a separate recommendation to the FCC addressing comprehensive changes to the fund, including a long-term cap that would affect all participating carriers.