During the Kurdistan Region’s referendum for independence from Iraq in 2017, an Iranian military commander told a Kurdish politician, “The United States is not the Kurds’ ally. In fact, it is not an ally of any of the Middle Eastern countries. The Americans are outsiders to the region. Sooner or later, they will leave you alone and will leave the Middle East.”It seems the Iranian officer has been proven right by the American withdrawal from northern Syria. Despite widespread international support across the political spectrum for the US to remain in Syria, and despite all the successes the Syrian Democratic Forces (SDF) and the Global Coalition to Defeat ISIS have achieved in their fight against terrorism in Syria, US President Donald Trump decided to leave northern Syria – and perhaps other territories – to Turkey.This decision will shape regional politics for years to come, as states and non-state actors in the Middle East will reconsider their relationship with the US: as the Trump administration seems to disregard longstanding American foreign policies, disciplines and principles. In regional capitals and public opinion, Trump’s decision is not seen as a mere betrayal of the Kurds, but as a signal that the US is far less reliable than Russia or Iran.Yet, there is a hope the US can correct its immature withdrawal following its decision to leave some soldiers there to protect the oil fields. However, this decision has further damaged America’s reputation in the region, as people see the Americans interested only in oil, and not in other American principles. The return of US forces should be a long-term strategy to rebuild northeast Syria, protecting it from Turkish aggression, ensuring the defeat of Islamic State and other terrorist groups, and showing nobility to protect the allies.Ever since George W. Bush launched “the war on terror,” the US has never been as successful as it has been against the Islamic State. The interventions in Afghanistan and Iraq have been incredibly costly in both human and financial terms, but the objectives have never been achieved. However, the US intervention in the fight against ISIS in Syria has been very successful, with lower costs to American forces and a smaller commitment of troops. The US war on terror would arguably not have been a success if America had not had the help of local allies, especially a strong, committed and principled force like the Kurdish-led SDF.SINCE 2012 – at the beginning the YPG and the YPJ Kurdish forces have secured Kurdish areas of northern Syria along the border with Turkey. This area – known in Kurdish as Rojava – has been a relatively progressive area in a hostile region. While imperfect, the SDF has guaranteed local autonomy through representative village councils and ensured the provision of services.The SDF and other Kurdish forces have kept Islamic State fighters in prison and worked to defend civilians from ongoing violence, allowing the United States to keep a light footprint in the area and to continue to harass the remnants of ISIS. But Trump’s decision last Sunday to withdraw troops from Rojava opened the door for Turkey to push out the Kurdish troops (as it has threatened to do for years), undoing the gains of the past five years.Trump’s decision to allow Turkey to enter northern Syria allowed the government of Recep Tayyip Erdogan to openly combat the Kurdish forces Ankara views as aligned with the Kurdish Workers Party (PKK), a militant group listed as a terrorist entity by Turkey, the United States and other countries. Turkey has invaded the Kurdish city of Afrin, where the Kurdish People’s Defense United (YPG) dominates.Turkey considers the YPG an offspring of the PKK, though the YPG has never attacked Turkey, and the PKK has not exploited the Syrian borders for its attacks on the Turkish Army. The Turkish state has a long history of opposing Kurdish political parties for nationalist reasons, and the current government views the Peoples’ Democratic Party (HDP) as a political threat. Several HDP members of parliament – including former cochairs of the HDP and thousands of members – have been in prison for years, and the mayors of three main Kurdish cities were removed.The US withdrawal will also open the door for Iran to assert itself further in regional issues. Iran, by supporting the Iraqi central government against the Islamic State and the government of Bashar Assad throughout the Syrian civil war, has already positioned itself as a regional power. But Iran is not popular among the Syrian population (nor among other regional players, aside from the Assad regime). The Iranian government has relationships with various Kurdish groups and the Syrian government, and while the Iranians are not eager to get directly involved in Rojava, Kurdish groups abandoned by the United States may look to Tehran as a new patron.THE EXPANSIONIST policies of Turkey, Iran and Russia (which is actively supporting Turkey and Iran) are destabilizing the region. The US-Turkish ceasefire agreement was soon ignored by Turkey as Erdogan met with Russian President Vladimir Putin and signed another deal on Syria. Their forces are not welcome in sensitive areas such as Kurdish regions, the Nineveh Plain and other minority areas, and the Gulf states oppose any support for Iran. At the same time, the Trump administration’s lack of commitment to any sort of foreign policy process leads foreign governments, groups and populations to respect the interventionist tendencies of Ankara, Tehran and Moscow.The US government has been looking for examples of state-building in which political partners could work to solve local problems while American forces provide security. The partnership with the SDF was one rare success, and it is gone due to a fit of short-term thinking. Despite changes in tactics from the other regional powers, Iran, Turkey and Russia have been relatively consistent in their approach, and Russian and Iranian commitments have been ironclad. The Americans’ commitments have not.The US administration needs to revisit its decision of withdrawing the troops so that the military successes will be translated to a political victory and long-term successes can be secured. The Coalition-SDF victories are at a dire danger to be nullified by the Turkish incursion. The recent history of the US engagement in the Middle East has proven that lack of long-term strategy and engagement only creates more distrust among local populations toward the US. The withdrawal of troops from Iraq in 2011 had disastrous consequences, leading directly to the rise of Islamic State.The US is the only force that can make sure the future of Syria will not remain at its current status; protect the Kurds not to be slaughtered by Turkish Army; secure enduring defeat of ISIS; and check Iranian expansionism and build hopes for the future of Syria. All the success and the possible future victories will be at risk if US troop withdrawal will not be reversed, and Turkish invasion will not be stopped.Even the most pro-American Kurds, the Kurds in Iraq, are questioning the loyalty of the US friendship. There are some internal debates whether the US can really guarantee the protection of the Kurds among brutal countries which are still oppressing them. The United States needs to bring its friends and allies in the Middle East together rather than leave them when its withdrawal is followed by ethnic cleansing by a US ally against another US ally.