The United States is legally required to supply Taiwan with defensive weapons. However, authorizing the multibillion-dollar, long-pending sale of the 66 planes would anger China, which regards the self-governing island as part of its territory.
The Obama administration is due to give its decision on the deal by Oct. 1. Lawmakers and analysts in both Taiwan and Washington widely anticipate that the administration will opt to upgrade Taiwan's existing fleet of F-16s, rather than sell the new, more advanced planes that the island has been seeking for several years.
The Pentagon spokeswoman for Asia-Pacific security affairs, Cmdr. Leslie Hull-Ryde, said Tuesday that no decisions have been made on potential arms sales to Taiwan and that the department does not comment on potential weapons systems for foreign military sales.
Sen. John Cornyn, R-Texas, who spoke to reporters by conference call after touring the Lockheed Martin factory in Fort Worth, said not approving the sale of new planes would be a blow for a crucial U.S. ally and could cost 2,300 jobs at the factory.
An amendment to the defense authorization bill could be introduced on the Senate floor, likely in October or November, to approve Taiwan's request, Cornyn said. If such an amendment were approved by Congress, Obama still would have the right of veto, but exercising it would mean scuttling approval for a wide array of defense programs.
In May, nearly half of the Democrat-led Senate sent a letter urging Obama to authorize the deal.
There is likely even broader support in the Republican-controlled House.
Giving the green light would set back Obama's efforts to cultivate a stable, cooperative relationship with China, which has reacted to previous arms sales to Taiwan by cutting military ties with the U.S.
Taiwan's President Ma Ying-jeou has forged closer ties with Beijing, reducing tensions across the Taiwan Strait to their lowest in six decades. But Ma, who faces re-election next year, sees the F-16s as a way of improving Taiwan's negotiating position with the communist government on the mainland.
Taiwan and China split amid civil war in 1949.