Hawks from both sides of the aisle are unhappy about the withdrawal of all U.S. troops from Iraq by year’s end, saying it will be a victory for Iran. Aside from President Obama, Defense Secretary Leon Panetta has talked about staying longer in Iraq. Sen. Joe Lieberman (I‑Conn.), Sen. Lindsay Graham (R‑S.C.), Sen. Scott Brown (R‑Mass.) and Mitt Romney, one of the leading Republican presidential contenders, all fear that withdrawal will embolden America’s enemies.

But they have their causation wrong: It was the overthrow of Saddam Hussein that handed Iran a victory on a silver platter. Americans should stop listening to the people who promoted this wrongheaded war in the first place, and remember the limitations and unintended consequences of our intervention.

Iraqi nationalism is still a potent force working against Iran’s outright annexation of Iraq. That said, Washington and Tehran have been actively competing for political influence in Iraq. Iran, however, has several distinct advantages that hawks would prefer to dismiss, and we ignore at our peril.

Let’s begin with Prime Minister Nouri al Maliki, head of Iraq’s Shi’a (Dawa) political party. From 1982 until the U.S.-led invasion in 2003, Maliki found refuge in Iran while other Dawa members found refuge in Syria. Why Iran and Syria? According to the Dawa website, “These two countries were most sympathetic to the cause against Saddam’s regime at the time.” During that time, Washington was assisting Saddam’s secular Ba’athist regime in its ongoing war against Iran. That balancing act came to an end after Saddam invaded Kuwait in August 1990.

Aside from Maliki, another advantage for Iran — again, long before the decision about the final troop withdrawal — was the act of deposing Saddam, which radically altered the balance of power in the Persian Gulf by removing the principal strategic counterweight to Iran. Today, Iran has expanded its influence across the region, including in Lebanon, Syria and Bahrain.

In Iraq specifically, Iran’s assistance to Shi’a militias, such as radical cleric and Mahdi Army leader Muqtada al Sadr, has alienated many Iraqis. But Iran has also sought to deepen its political and economic influence by providing hospital treatment and surgery for wounded Iraqis, supplying Iraq with millions of liters of kerosene a day, and using other forms of soft power leverage to expand its “strategic depth” in Iraq.

Another factor facilitating Iran’s maneuvering in Iraq and at the root of the two countries’ ethno-linguistic and historical ties is the shared border between them. By divorcing Iraq from its regional context, hawks remind us of the ignorance they broadcast when they first promoted the war.

Even with nearly 4,500 U.S. service members killed, more than 100,000 Iraqis slain and more than $800 billion spent — the meter’s still running — hawks would prefer to see U.S. troops continue to fight and die to somehow peel back Iran’s political gains in Iraq.

Sen. John McCain (R‑Ariz.) has called America’s impending withdrawal from Iraq a “consequential failure” and “a strategic victory for our enemies in the Middle East, especially the Iranian regime, which has worked relentlessly to ensure a full withdrawal of U.S. troops from Iraq.” Frederick Kagan, one of the intellectual architects of the 2007 troop “surge,” wrote in a blog post: “The withdrawal of American military protection from a state helpless to defend itself on its own effectively throws Iraq into the arms of Iran, however the Iraqis feel about the matter.”

Even Obama is taking unwarranted credit for allegedly sticking to his campaign pledge to have U.S. forces removed. His administration lobbied the Maliki government for maintaining a residual troop presence in Iraq and is now planning a continued combat presence in the Persian Gulf.

For many hawks, staying the course in Iraq is not enough. Many of them now advocate a military strike on Iran, a country with three times the population and four times the territory of Iraq.

Those who years ago were gullible enough to believe that Iraq would be a “cakewalk” are today worthy only of being ignored.