The White House battled on Sunday to secure eight more weeks of political sustenance for President George W Bush's Iraq strategy, but the clock is running down fast on his authority to wage the war.
While the Bush administration may stifle a Republican revolt until after a key report by US commander in Iraq General David Petraeus in mid-September, the patience of veteran party statesmen is almost spent.
Asked if the current mission would pass if it were put up for a vote on Sunday, Senator John Warner said on ABC television: "I doubt very much that it would."
Senators Warner and Richard Lugar on Friday made what may turn out to be a pivotal attempt to force Bush to change course and curtail his "surge" of nearly 30,000 extra troops into Iraq.
They proposed that Congress should reauthorise a sharply narrowed US mission in Iraq, to pull troops out of the sectarian cross-fire, and retask them to battle terrorists, train Iraqi soldiers and secure Iraq's borders.
In a blizzard of appearances on US networks' on Sunday talk shows, National Security Adviser Stephen Hadley said the White House took the intervention of respected figures like Warner and Lugar seriously.
"But the time to begin that process is September. And the opening shot really ought to be to hear from the commanders on the ground who can make an assessment of where we are in our strategy," he said on ABC.