Leaked Pentagon papers showed in early April that the United States is allegedly following the inner workings of Russia’s intelligence operations and is also spying on Ukraine, adding a new dimension to the US involvement in the Ukraine war.

While the US has not actually declared war against Russia, the documents show that it continues to support Ukraine with military intelligence as well as money and weapons against the Russian invasion.

There is no end in sight to the war between Ukraine and Russia – nor to US involvement. While it is far from the first time that the US became a third party to war, this scenario brings the Iraq War, in particular, to mind.

I am a scholar of international relations and an expert on international conflicts. A comparison with the Iraq War, I believe, offers a useful way to look at the case of Ukraine.

The Iraq and Ukraine wars have notable differences from a US foreign policy perspective – chiefly, thousands of American soldiers died fighting in Iraq, while the US does not have any ground troops in Ukraine. But assessing the Iraq War, and its long aftermath, can still help articulate concerns about the United States getting involved in intense violence in another faraway place.

Here are three key points to understand.

An image of Saddam Hussein printed on copper, part of Iraqi valuables seized by law enforcement agents, at the Iraqi Cultural Center in Washington in 2011. Credit: Reuters

1. Intervention doesn’t guarantee success

Around the time former President George W Bush announced the US would invade Iraq in 2003, Osama bin Laden, the wealthy Saudi Arabian Islamist who orchestrated the September 11, 2001, attacks, remained at large. While not obviously connected, the fact that bin Laden continued to evade the US contributed to a general sense of anger at hostile regimes. In particular, Saddam Hussein defied the US and its allies.

The Iraqi dictator continued to evade inspections by the United Nations watchdog group the International Atomic Energy Agency, giving the impression that he had weapons of mass destruction. This proved maddening to the US and its allies as the cat and mouse game dragged on.

Bush reportedly had intense concerns about whether Saddam could use alleged weapons of mass destruction to attack the US, causing even more harm than 9/11 did.

A US-led coalition of countries that included the United Kingdom and Australia invaded Iraq in March 2003. The “coalition of the willing”, as it became known, won a quick victory and toppled Saddam’s regime.

Bush initially enjoyed a spike in public support immediately after the invasion, but his polls shortly after experienced a downward trajectory as the war dragged on.

However, the US showed very little understanding of the politics, society and other important aspects of the country that it had taken the lead in occupying and then trying to rebuild.

Many decisions, most notably disbanding of the Iraqi Army in May 2003, revealed poor judgment and even outright ignorance because, with the sudden removal of Iraqi security forces, intense civil disorder ensued.

Disbanding the army caused insurgent militant forces to come out into the open. The fighting intensified among different Iraqi groups and escalated into a civil war, which ended in 2017.

Today, Iraq continues to be politically unstable and is not any closer to becoming a democracy than it was before the invasion.

2. Personal vendettas cannot justify a war

During his 24-year regime, Saddam lived an extravagant lifestyle coupled with oppression of civilians and political opponents. He engaged in genocide of Kurdish people in Iraq. Saddam was finally executed by his own people in 2006, after US forces captured him.

Putin is equally notorious and even more dangerous. He has a long track record of violent oppression against his people and has benefited from leading one of the world’s most corrupt governments.

He also actually possesses weapons of mass destruction and has threatened multiple times to use them on foreign countries. Saddam and Putin have also both been the direct targets of US political leaders, who displayed a fixation on toppling these foreign adversaries, which was evident long before the US actually became involved in the Iraq and Ukraine wars.

The United States’ support for Ukraine is understandable because that country is fighting a defensive war with horrific civilian casualties. Backing Ukraine also makes sense from the standpoint of US national security – it helps push back against an expansionist Russia that increasingly is aligned with China.

At the same time, I believe that it is important to keep US involvement in this war within limits that reflect national interests.

Demonstrators rally in front of the US Capitol calling for an end to the war in Iraq, in Washington in 2007. Credit: Reuters.

3. It can divide the country

The Iraq War resulted in a rise in intense partisanship in the US over foreign policy. In addition, recent opinion polls about the Iraq War show that most Americans do not think that the invasion made the US any safer.

Now, the U.S. faces rising public skepticism about getting involved in the Ukraine war, another expensive overseas commitment.

Polls released in January 2023 show that the percentage of Americans who think the US is providing too much aid to Ukraine has grown in recent months. About 26% of American adults said in late 2022 that the U.S. is giving too much to the Ukraine war, according to Pew Research Group. But three-fourths of those polled still supported the U.S. engagement.

The average American knows little to nothing about Iraq or Ukraine. Patience obviously can grow thin when US.support for foreign wars becomes ever more expensive and the threat of retaliation, even by way of tactical nuclear weapons, remains in the realm of possibility. Aid to Ukraine is likely to become embroiled in the rapidly escalating conflict in Washington over the debt ceiling.

On the flip side, if the US does not offer sufficient support for Ukraine to fend of Russian attacks and maintain its independence, adversaries such as Russia, China and Iran may feel encouraged to be aggressive in other places.

I believe that the comparison between the wars in Iraq and Ukraine makes it clear that US leadership should clearly identify the underlying goals of its national security to the American public while determining the amount and type of support that it will give to Ukraine.

While many people believe that Ukraine deserves support against Russian aggression, current policy should not ignore past experience, and the Iraq War tells a cautionary tale.

Patrick James is Dornsife Dean’s Professor of International Relations, USC Dornsife College of Letters, Arts and Sciences.

This article was first published on The Conversation.