The bond between the United States and Yemeni leader Ali Abdullah Saleh cannot be minimized. Saleh allowed the US government, despite great personal peril, to operate inside his country and attack Al Qaeda in the Arabian Peninsula repeatedly over the past couple years. Saleh has been a stalwart on counter-terrorism policy, and the US rewarded him for it. There are other countries where Arab leaders are facing serious threats to their legitimacy from street protests, but the US hasn’t thrown them overboard. And that appeared to be the case in Yemen, where the US would offer pro forma statements about the uprising and the need for Saleh to be more responsive to his people and allow them more democratic participation, but nothing more. But that has changed.

The United States, which long supported Yemen’s president, even in the face of recent widespread protests, has now quietly shifted positions and has concluded that he is unlikely to bring about the required reforms and must be eased out of office, according to American and Yemeni officials.

The Obama administration had maintained its support of President Ali Abdullah Saleh in private and refrained from directly criticizing him in public, even as his supporters fired on peaceful demonstrators, because he was considered a critical ally in fighting the Yemeni branch of Al Qaeda. This position has fueled criticism of the United States in some quarters for hypocrisy for rushing to oust a repressive autocrat in Libya but not in strategic allies like Yemen and Bahrain.

That position began to shift in the past week, administration officials said. While American officials have not publicly pressed Mr. Saleh to go, they have told allies that they now view his hold on office as untenable, and they believe he should leave.

You can ask when this changed. It seems pretty clear to me. Saudi Arabia gave up on Saleh two weeks ago. About a week later, the US tries to nudge him out the door. Period, end of story.

The more you look at the US response to the Arab uprising, the more you see this relationship between them and the major Sunni power in the region. The Saudis gave up on Saleh, and now the US has followed suit. The Saudis entered Bahrain with security forces, and the US has said little. The Saudis repressed their own people, and I don’t even think the pro forma press release went out from the White House on that one. And the Saudis joined the Arab League assent to intervention in Libya, and the US warplanes flew overhead.

Saudi Arabia is one of two regional powers, with the other being Iran. The balance of power has tilted in favor of the Iranians, particularly after the Shiite restoration in Iraq. So there’s a geopolitical element to following the Saudi lead on the uprisings as well. We’re not just seeing an appeal to authority, we’re seeing a direct effort to bolster a regional power.

In this case, the Yemeni leader has lost the legitimacy of many of his citizens, so it could be the right move from a democratic standpoint. But the Obama Administration hasn’t stepped out on that ledge in any other case without a clear signal from the Saudis.