Two powerful Senate chairmen are questioning plans to withdraw all U.S. troops from Afghanistan by May 1, providing potential cover for President Biden to change his mind as he faces a rapidly approaching deadline.

Why it matters: The war is America’s longest and most costly. Former President Trump negotiated a departure timetable with the Taliban, and his successor has indicated he’s ready to honor that commitment.

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• The unstable environment on the ground, as well as the politics of making such a bold move, have put increasing pressure on Biden as the clock winds down.

Driving the news: Sen. Bob Menendez (D-N.J.), chair of the Senate Foreign Relations Committee, said last week that Biden may have to reconsider the deadline. He told reporters he’s concerned about “the viability” of the peace process in Afghanistan.

• Menendez drove home his hesitancy to Axios on Wednesday.
• “We have to look at the realities of what’s happening in Afghanistan. It seems to me the Taliban is not meeting its obligations. After so many (American) lives and national treasure, we need to make sure that when we leave, we leave in a way that can provide stability.”
• Sen. Jack Reed (D-R.I.), chair of the Armed Services Committee and an Army veteran, has gone even further: He said Biden should not withdraw all forces and is worried having no presence in the region could give way to further terrorist attacks.
• “I would expect some extension,” Reed ultimately said of the timeframe.

But, but, but: Beyond the chairmen’s unity, congressional Democrats are all over the map.

• Sen. Mark Kelly (D-Ariz.), a Navy veteran who served in the region for several years, told Axios, “May 1 is pretty quick.”
• Sen. Joe Manchin (D-W.V.), an important swing-state lawmaker, said: “Anytime we have invested that much blood and treasure in an area that has no more of an outcome or stabilization, then you have to reevaluate. But what happens if you do leave at this point in time?”
• Sen. Elizabeth Warren (D-Mass.), a key figure on the progressive left, told Axios that Biden needs to get out now: “There will always be a reason to delay, but President Biden is committed to meeting this deadline. I support him in that.”

The latest: The Biden administration has proposed plans for an interim, power-sharing agreement between the Taliban and Afghan leaders before May 1. It would be supported by neighboring countries and the United Nations.