Talks between Zalmay Khalilzad and Mullah Abdul Ghani Baradar on Feb. 25 in Doha, Qatar. (Qatar Ministry of Foreign Affairs via AP)

THE TRUMP administration has now conducted five rounds of negotiations with the Taliban, including a grueling 16-day round that ended Tuesday in Qatar. Both sides are claiming progress, but details have been scant — including, it turns out, for the Afghan government, which has been excluded from the talks. That prompted an undiplomatic outburst Thursday by the national security adviser to President Ashraf Ghani, who told reporters in Washington that the U.S. administration is “ostracizing and alienating a very trusted ally.”

A negotiated peace in Afghanistan is much to be wished for. But judging from what has been reported from Qatar, the Afghan government is right to be concerned — as are Americans who don’t favor throwing away all that the U.S. Afghan mission has accomplished since 2001, at enormous cost. According to administration envoy Zalmay Khalilzad, the talks are focusing on two issues: preventing al-Qaeda and other terrorist groups from using Afghanistan as a base for attacks, and a withdrawal timeline for U.S. troops.

Mr. Khalilzad tweeted that an accord would need to include two other elements: “intra-Afghan dialogue and a comprehensive ceasefire.” But he said talks including the Taliban and Afghan government would begin only after the “agreement in draft” on the U.S. withdrawal and terrorism “is finalized.” That suggests that the United States would commit itself to a pullout timetable before an Afghan peace process even starts up, and that there might be no link between the U.S. drawdown and a final settlement.

If so, that would be a dangerous yielding of U.S. leverage that could all but doom the Afghan government — and the millions of Afghans, especially women, who prize the civil society that lives under its umbrella. Though it may have softened its oppression in some areas it controls, the Taliban has given no indication it is prepared to accept a democratic political system, share power with the Ghani government or respect basic human rights. On the contrary, its leaders have portrayed themselves in recent public statements as victors in the war who are preparing to reap their rewards.

Mr. Khalilzad ’s negotiating strategy may suit the priorities of President Trump, who has made it clear he wishes to withdraw U.S. troops as quickly as possible and has little interest in the consequences for Afghans. But the notion that, in the absence of a peace settlement, the Taliban could be relied on to prevent terrorism looks naive. As former CIA deputy director Michael Morell and former defense undersecretary Mike Vickers bluntly concluded in a Post op-ed, “the most likely outcome” of a U.S. withdrawal is “the Taliban will take over, and it will offer haven to al-Qaeda, which will again target the U.S. homeland.”

Mr. Khalilzad ’s efforts should continue. But the administration ought to insist that the Taliban accept a U.S. timeline for withdrawal measured in years rather than months; and it should be clear that the last forces will not depart until there is an Afghan peace accord — not just a cease-fire and talks. In the meantime, it should keep Mr. Ghani’s government fully briefed.