Editor’s Note: Julian Zelizer is a professor of history and public affairs at Princeton University and a New America fellow. He is the author of “Jimmy Carter” and “The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society.” The opinions expressed in this commentary are solely his.

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Republican candidates have been dealing with questions about the Iraq War

Julian Zelizer says unpopular wars linger in politics for decades -- and then there's ISIS

CNN  — 

Iraq isn’t going away anytime soon.

Over the past few weeks, Republican presidential candidates have been scrambling to explain what their position is on the war that was launched under President George W. Bush.

Julian Zelizer

His brother, former Florida Gov. Jeb Bush, bobbed and weaved in both directions. First he explained that he would have supported the war if he had been president, and then he tried to walk back from what he said when confronted with a backlash over his remarks.

Upon dealing with similar questions as his fellow Floridian, a normally smooth Sen. Marco Rubio stumbled all over his words. Former New York Gov. George Pataki and Sen. Lindsey Graham of South Carolina have raised some eyebrows by calling for a substantial increase in ground troops to combat ISIS.

The reality is that controversial and unpopular wars continue to shape politics long after the conflicts are over. Nobody knows this more than the Democratic Party.

During the first part of the 20th century, President Woodrow Wilson led the nation through the brutal battles of World War I, a complex war that ended with a bitter partisan conflict within the United States over the creation of the League of Nations. The debate pitted Senate Republicans against the commander in chief. Wilson had promised a war to end all wars, but the messy outcome didn’t give many people confidence this would be the case.

For the next two decades, U.S. presidents, including Democrat Franklin Roosevelt, had to govern under the shadow of that war. The political pressure from both parties against any kind of overseas intervention remained intense, one of the biggest obstacles that Roosevelt had to overcome as the threats from Germany and Japan mounted. It also took some time for Democrats to win back progressives in the fold since so many were profoundly disillusioned with Wilson’s domestic wartime record, such as the suppression of civil liberties.

Politics: GOP grapples with ground troops in Iraq

Although the decisive and triumphal victory of the United States and its allies in World War II in the defeat of Germany and Japan seemed to cement the credentials of the Democratic Party on national security, that consensus didn’t last long in the world of politics. Democrats saw their political advantage on national security fade quickly as a result of the stalemate in Korea. Republicans used the issue of Korea, combined with the fall of China to communism in 1949, as a battering ram against the Democrats on foreign policy.

In the 1952 elections, Democrat Adlai Stevenson watched as Republican Dwight Eisenhower won the White House and Republicans took control of Congress with national security being a central theme. In one of his last public speeches before the election, Eisenhower, a military hero, simply stated: “I shall go to Korea.” The Korean War, he said, was a “symbol – a telling symbol – of the foreign policy of our nation. It has been a sign – a warning sign – of the way the administration has conducted our world affairs.”

There was an entire generation of Democrats scarred by this election, including Sen. Lyndon Johnson, and they would spend much of their time doing everything to avoid falling victim to the attack of being weak on defense.

Those fears helped to push Democrats into a deep commitment to the war in Vietnam, which killed 58,000 members of the U.S. military. And the unsuccessful outcome of the war in Vietnam was damaging for Democrats for decades to come.

While liberals within the party believed that the war had been a poor decision and was evidence that military force was often the wrong solution, right-wing conservatives offered a different interpretation. Republicans claimed that Democrats had failed to unleash the nation’s full bombing arsenal and had “cut and run” in 1973, allowing South Vietnam to fall to communism.

Republicans used Vietnam as a talking point to build support for a huge military buildup in the 1980s. President Ronald Reagan spoke about Vietnam as a “noble cause.” He charged that Jimmy Carter had learned the wrong lesson from the war. It was not the case that the United States should avoid using military power but, rather, the nation needed not to be “afraid” to “win.” Democratic presidential candidates always struggled to respond to these charges.

Republicans had some controversial military legacies of their own to reckon with before 9/11. Richard Nixon’s brutal and secretive bombing campaign against communist forces in South Asia raised ongoing questions when Republicans were in power about their willingness to circumvent Congress and the public in conducting their policies.

Reagan’s war in Central America exploded in controversy when the Iran-Contra investigation revealed that National Security Council officials had violated legislative prohibitions against assisting the Nicaraguan Contras and that the president, despite his rhetoric, had sold arms to Iran. When President George H.W. Bush decided he would not send in U.S. forces to take out Saddam Hussein in Operation Desert Storm and when he refused to send U.S. troops to intervene in a number of major humanitarian crises, Democrats such as Bill Clinton accused the GOP of being too timid in using military force.

Iraq was more problematic politically for the Republicans than any of these precedents. The war opened up the same kind of struggle within the GOP that Democrats had long faced. It has forced Republican politicians to take a stance on whether President George W. Bush committed troops to a war that was both costly and unnecessary.

It has raised the question of whether regime change was the right way to fight the war on terrorism. It has brought up the issue of whether their party used false intelligence or manipulated information about Iraq’s possession of weapons of mass destruction to build support for a military operation. It has forced Republicans to defend their record on fighting the post-9/11 threat.

In addition, the war has never really ended. On Sunday, U.S. Defense Secretary Ash Carter offered extremely critical comments about the Iraqi military, describing the fall of Ramadi to ISIS as a sign that the defenders were unwilling to fight.

The battle against ISIS is partly an extension of the processes unleashed by regime change in Iraq and some of the failures to think through the best options for reconstructing a stable government regime to replace Hussein. The fact that the war goes on, even in limited fashion, will continue to push this to the top of the agenda.

Even though Republicans were in control in Washington when the Iraq War began, it drew backing from Democrats, including their strongest 2016 contender, Hillary Clinton. And the issue of what to do about ISIS means Clinton will have to deal with the Iraq War issue as her candidacy moves ahead.

If history is a guide, which it is, Iraq won’t go away anytime soon. Republican candidates will have to wrestle with the legacy of that war for many years to come. The fact that Iraq remains a big issue is not surprising. What is surprising is the fact that so many candidates in the GOP don’t seem prepared to put forward their responses. Iraq will remain one of the defining issues in party politics for decades to come.

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