Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the original estimate made in 2006. The soaring cost prompted a key member of Congress to raise questions about continued U.S. support for the project, which aims to make fusion power feasible. "I'm really beginning to believe that our involvement in ITER is not practical," said Senator Dianne Feinstein (D–CA), the head of a spending panel that controls ITER funding. Her panel could soon move to cut next year's spending on the project, proposed to be $150 million. The House of Representatives and the White House, however, would have to sign off on any move to withdraw from the ITER commitment, which some U.S. diplomats view as unthinkable. Still, ITER leaders are worried that if the United States withdraws, the entire project could be in jeopardy.