The withdrawal of the United States troops from Iraq began in December 2007 with the end of the Iraq War troop surge of 2007 and was mostly completed by December 2011, bringing an end to the Iraq War. The number of U.S. military forces in Iraq peaked at 170,300 in November 2007. The withdrawal of U.S. military forces from Iraq was a contentious issue in the United States for much of the 2000s. As the war progressed from its initial invasion phase in 2003 to a nearly decade-long occupation, American public opinion shifted towards favoring a troop withdrawal; in May 2007, 55% of Americans believed that the Iraq War was a mistake, and 51% of registered voters favored troop withdrawal. In late April 2007 Congress passed a supplementary spending bill for Iraq that set a deadline for troop withdrawal but President George W. Bush vetoed this bill, citing his concerns about setting a withdrawal deadline. The Bush administration later sought an agreement with the Iraqi government, and in 2008 Bush signed the U.S.–Iraq Status of Forces Agreement. It included a deadline of 31 December 2011, before which "all the United States Forces shall withdraw from all Iraqi territory". The last U.S. troops left Iraq on 18 December 2011, in accordance with this agreement. In 2014, the advance of the Islamic State of Iraq and the Levant (ISIL) from Syria to Iraq's western provinces prompted the U.S. to intervene again, alongside other militaries, to combat ISIL. In January 2019, Secretary Pompeo put the number of U.S. troops in Iraq at approximately 5,000. In early 2020 the Iraqi parliament voted to withdraw all remaining troops and the Iraqi Prime Minister told the U.S. to start working on troop withdrawal. Background Polling Immediately before and after the 2003 invasion, most polls within the United States showed a substantial majority supporting war, though since December 2004 polls consistently showed that a majority thought the invasion was a mistake. In the spring of 2007, surveys generally showed a majority in favor of setting a timetable for withdrawal. However, in this area responses can vary widely with the exact wording of the question. Surveys found that most preferred a gradual withdrawal over time to an immediate pullout. 2004 U.S. Presidential election The issue was one on which John Kerry and George W. Bush differed in the 2004 U.S. presidential election. Kerry said in August 2004 that