Aaron David Miller is a vice president and distinguished scholar at the Woodrow Wilson International Center for Scholars and author of "The End of Greatness: Why America Can't Have (and Doesn't Want) Another Great President." Miller was a Middle East negotiator in Democratic and Republican administrations. Follow him @aarondmiller2 . Richard Sokolsky is a senior fellow at the Carnegie Endowment for International Peace. From 2005-2015, he was a member of the Secretary of State's Office of Policy Planning. The views expressed are their own.

Egyptian President al-Sisi arrives for meetings Monday with President Trump. Jordan's King Abdullah is due on Wednesday. Last month, the Saudi King's influential son, Deputy Crown Prince Mohammed bin Salman, showed up for what were hailed as breakthrough meetings with the president and administration officials.

Trump seems to be banking heavily on the Sunni states to play a major role in achieving his administration's objectives in the region.

American and Sunni interests overlap on certain issues but are hardly identical across the board. And in any event, Arab states are looking for Washington to do most of the heavy lifting.

Indeed, based on past performance, Arab promises are likely to fall short of the President's expectations.

Defeating ISIS

While the Trump administration has emphasized the importance of defeating ISIS, that goal is not the highest priority for the Sunni Arabs.

Given his country's small size, Jordan's King Abdullah is one of the few Arab leaders who has played an outsized role in battling ISIS in Syria, largely through intelligence sharing and providing facilities. Jordan has also accepted hundreds of thousands of Syrian refugees.

But at best, the Sunni states have played a marginal and symbolic role in the war against the Islamic State. The seven countries most heavily involved in this campaign are all America's allies in Europe and the Asia-Pacific region.

Egypt is battling ISIS-affiliated Islamic militants in the Sinai -- not terribly effectively -- but has contributed nothing to coalition operations in Syria. Turkey's primary military agenda in Syria is focused against the Kurds. The Saudis and their Sunni allies in the Persian Gulf have prioritized the removal of Syrian President Bashar al-Assad over the defeat of the Islamic State. And since the Saudi military intervention in Yemen in March 2015, Riyadh has placed a higher priority on containing Iran than defeating ISIS (or AQAP).

Reconstructing Syria and Iraq

Ditto for contributions the Sunnis are likely to make to fix Iraq and Syria once the ISIS caliphate is defeated. Earlier this year, the Saudis appeared to have supported President's Trump's call for safe zones in Syria and has offered to send troops to that war-torn country. But it's unclear what this means in practice and whether it will ever materialize.

Key Sunni states are risk-averse and divided on Syria. Egypt seems ready to acquiesce in Assad's staying; the Saudis want to toss Assad under a bus; and Turkey seems ready to cut a deal with anyone who's willing to check the aspirations of the Syrian Kurds. Nor is a Shia-dominated Iraqi government, heavily influenced by Iran, likely to be open to allowing Sunni states to gain sway there.

For all their professed desire to contain Iran, Sunni states will be reluctant to send troops or peacekeepers to Iraq or to Syria to protect the "interim zones of stability" the United States has proposed if it means risking a confrontation with a more muscular Iran that they are certain to lose.

Nor will they agree to serve as an ATM for financing reconstruction of post-ISIS Syria if the main beneficiaries of Saudi largesse are the Assad regime, Iran, and Russia. The Trump Administration's acceptance of Assad's rule won't help matters.

And any Syrian reconstruction effort that can't or won't address areas under Assad's control -- the capital and all major Syrian cities -- isn't much of a reconstruction enterprise.

Containing Iran

President Trump may also find Sunni Arab partners reluctant to risk challenging Iran without the cover of a robust US role. Many of them, like Egypt and Jordan, do not share Saudi Arabia's animus toward Iran and have zero interest in taking on Tehran militarily. Riyadh talks tough about cutting the Iranians down to size, but the Saudis are unwilling to do so unless they can hide under Uncle Sam's coattails.

The Sunni Arabs would love to see the US confront Iran in Syria and Iraq. But the options are limited and risky, and they would jeopardize US counter-terrorism priorities. In Yemen, the Trump administration is signaling that it intends to provide even more support to the Saudis than Obama did -- further emboldening Riyadh. Indeed without that support, it's doubtful the Saudis would be acting as boldly — and recklessly.

It is simply not in US interests to be dragged into an interminable war against the Houthis in Yemen and have its image blackened by Saudi military actions that have resulted in the deaths of thousands of Yemeni civilians. Iran is clearly taking advantage of a local conflict in Yemen to expand its influence; but Saudi actions are only making matters worse.

Achieving Israeli-Palestinian peace

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The Sunni Arabs are almost certain to disappoint Trump on Israeli-Palestinian peace, too. There's little doubt that Israel and the Arab states have grown closer over their common stance regarding threats posed by Iran and jihadists. But it is doubtful this new alignment will extend to peacemaking unless Israel is prepared to make significant concessions to the Palestinians and the Arabs are ready to lower their horizons.

The 2002 Arab summit outlined an Arab peace plan whose trade-offs go well beyond what the Netanyahu government has been prepared to offer. If President Trump wants to get the Arab states to make peace with Israel, he'll need to bring serious pressure on both sides, particularly on issues such as borders and Jerusalem. Right now there's zero evidence that anyone, including Trump, is ready for that.

The bottom line on the Sunni Arabs is that most are too divided, risk averse, self-interested and wary of Washington to be agents of the US's Middle East agenda. At best, they might be junior partners, a role that UAE special forces seem to be playing effectively in the fight against AQAP in Yemen. But Washington cannot count on these countries to take a lead role in waging war or making peace effectively in this profoundly polarized and fractured region.

Indeed if the US wants something done, it will face the unpalatable and extremely risky prospect of doing it itself.