One of the most curious features of the Obama administration’s foreign policy is the contrast between the silky, non-confrontational public diplomacy it employs when dealing with dictatorships and adversaries, such as Russia, China and Venezuela — and the brusqueness with which it often addresses U.S. clients and allies.

The latest example of this came last week in Iraq, where the United States is engaged in a complex and high-stakes competition with Iran. At immediate issue is whether Iraq’s Shiite-led government will ask Washington to leave behind 10,000 or so soldiers of the 47,000 troops now there, instead of completing a full withdrawal by the end of this year.

The larger question is whether Iraq will be forced by a full U.S. pullout to become an Iranian satellite, a development that would undo a huge and painful investment of American blood and treasure and deal a potentially devastating blow to the larger U.S. position in the Middle East.

The administration has made it fairly clear that it is willing to make a deal to leave behind some troops. But coaxing the fragmented and prickly Iraqi leadership into making the right choice would require subtlety, patience and high-level engagement — like that the Bush administration employed when it negotiated a strategic framework with Iraq before leaving office in 2008, or that Vice President Biden used in helping to broker an agreement on a new Iraqi government last year.

So it was startling to hear Defense Secretary Leon Panetta offer, in Baghdad, the following description of his message to Iraqi leaders: “Dammit, make a decision.”

The tone of that remark, like other administration rhetoric on the potential deal, suggests that Obama and his top aides believe they are offering Iraqi Prime Minister Nouri al-Maliki a favor by inviting a request to leave troops behind, and don’t think a stay-on force is a vital U.S. interest.

Others see it quite differently. Maliki, like U.S. commanders in the Middle East, understands very well that without an American military presence, Iraq will be unable to defend itself against its Persian neighbor. Iranian-backed militias are already stepping up attacks on U.S. and Iraqi forces with sophisticated rockets and roadside bombs; without U.S. help, Iraqi forces cannot easily counter them. Moreover, Iraq’s conventional forces are no match for those of Iran.

Consequently, argues Frederick Kagan of the American Enterprise Institute, Maliki and his government face a fateful choice. “If Maliki allows the United States to leave Iraq,” Kagan wrote in a recent report, “he is effectively declaring his intent to fall in line with Tehran’s wishes, to subordinate Iraq’s foreign policy to the Persians, and possibly, to consolidate his own power as a sort of modern Persian satrap in Baghdad.”

Alternatively, Iraq could use its burgeoning oil revenue to rush to construct an army and air force capable of countering Tehran. But either development would be regarded as a strategic threat by Saudi Arabia and other Persian Gulf states.

Most Iraq watchers believe Maliki wants to ask for U.S. troops. But the problems — in addition to the chronic Iraqi practice of putting off hard decisions until the last minute — are formidable. Perhaps the most serious is Maliki’s political dependence on the Shiite party of Moqtada al-Sadr, an Iranian client. Sadr is threatening armed resistance if U.S. troops stay, and the offensive already underway by Iranian-sponsored militias shows that Tehran is ready to fight.

Administration officials nevertheless argue that the danger of Iranian hegemony in Iraq — and hence the importance of a stay-on force — is overstated by analysts such as Kagan. “Iran is struggling with its own economy,” Antony Blinken, a senior aide to Biden, told me. “Infighting among Iranian leaders has undercut its ability to make decisions about domestic and foreign policy,” and the uprising against the Syrian regime has further shaken Tehran’s confidence.

Maliki, Blinken says, has proven himself a nationalist who will resist Tehran’s diktats, and Iraqis will not tolerate a Persian puppet. And even if all American troops leave, a strong U.S. diplomatic contingent will remain, which, together with arms sales and a embassy-based military liaison group, should ensure continuing U.S. influence.

The only Obama administration official who has publicly made the case for a continued U.S. military presence is former defense secretary Robert M. Gates. In a speech in May, he said it would send “a powerful signal to the region that we’re not leaving, that we will continue to play a part.” He added: “I think it would be reassuring to the Gulf states. I think it would not be reassuring to Iran, and that’s a good thing.”

Gates publicly urged Iraq to keep U.S. troops. Now he is gone, and the message is “dammit, make a decision.” Whether or not Iran is prepared to seize hold of Iraq, those aren’t the right words to keep an ally.