2001: Voted for the Authorization for Use of Military Force after the Sept. 11, 2001, attacks, which became the basis for counterterrorism operations in the Middle East.
2009: Voted to prevent President Barack Obama from releasing Guantanamo Bay detainees.
2013: Voted against easing restrictions on transferring detainees out of Guantanamo Bay.
2015: Vowed to continue the US drone program, but has raised concerns about civilian casualties.
2015: Accused Saudi Arabia, the United Arab Emirates, Kuwait and Qatar of doing too little to fight the Islamic State due to their preoccupation with Yemen's Houthis.
2016: Voted to block a $1 billion tank sale to Saudi Arabia.
2017: Voted to block a $500 million missile sale to Saudi Arabia.
2018: Called for sanctions on Saudi Arabia for the murder of Jamal Khashoggi.
2018: Voted to block a $300 million missile sale to Bahrain.
May 2019: Passed a war powers resolution to end US support for the Saudi-led coalition in Yemen but failed to gain enough votes to override President Trump's veto.
June 2019: Voted to block a $750 million missile sale to Bahrain.
June 2019: Voted to block a $3 billion sale of attack helicopters to Qatar.
June 2019: Voted to block $8 billion in arms transfers to Saudi Arabia and the United Arab Emirates.
July 2019: Criticized Saudi Arabia for treating women "like third-class citizens."
July 2019: Vowed to "sit down in a room" for negotiations with Saudi leadership.
July 2019: Accused Saudi Arabia of trying to "drag the US into a conflict with Iran" and said Riyadh needs to be "part of the solution" to regional stability.
2007: Voted against declaring the Islamic Revolutionary Guard Corps a terrorist organization.
2010: Voted for more Iran sanctions.
2015: Voted in favor of the nuclear deal.
2017: Voted along with only one other senator against additional Iran sanctions.
2018: Opposed President Trump's withdrawal from the nuclear deal and supports reentering the agreement.
June 2019: Voted to prohibit funding for military action against Iran absent congressional authorization.
July 2019: Vowed to "sit down in a room" for negotiations with Iranian leadership.
1991: Voted against the first Gulf War.
1998: Opposed President Bill Clinton's airstrikes against Iraq.
2002: Voted against the Authorization for Use of Military Force in Iraq.
2007: Opposed President George W. Bush's troop surge in Iraq and called for US withdrawal.
2007: Voted for the Biden resolution calling for a federalized Iraq along sectarian and ethnic lines.
2015: Supported President Obama's airstrikes against the Islamic State but called for limits on US ground troops.
1995: Voted against moving the US Embassy in Israel to Jerusalem.
2016: Skipped AIPAC's annual conference during his presidential bid to deliver a speech in Utah criticizing Israel's occupation of the West Bank, its blockade of the Gaza Strip and its 2014 military offensive against Hamas.
2017: Voted for a pro-Israel resolution in favor of moving the US Embassy to Jerusalem.
2017: Floated military aid cuts to Israel in an interview with The Intercept.
2017: Co-signed a letter to Israeli Prime Minister Benjamin Netanyahu urging him not to demolish a West Bank village and opposing settlement expansion.
2018: Opposed President Trump's relocation of the US Embassy to Jerusalem.
2018: Opposed President Trump's elimination of Palestinian aid.
2018: Condemned Israel for firing on Palestinians during Gaza border protests.
2018: Endorsed by liberal lobbying group J Street for his Senate reelection bid.
2018: Labelled Prime Minister Netanyahu's government "racist."
February 2019: Voted against anti-BDS legislation over free speech concerns.
July 2019: Endorsed using military aid to Israel as leverage to change the government's behavior.
July 2019: Vowed to "sit down in a room" for negotiations with Israeli and Palestinian leadership.
2003: Voted for Syria sanctions package.
2013: Expressed skepticism of President Obama's push to arm Syrian opposition groups against President Bashar al-Assad.
2013: Supported President Obama's UN-backed deal with Russia to remove chemical weapons from Syria.
2014: Supported US airstrikes against the Islamic State but voiced "concerns" over arming Syrian opposition groups in the fight.
2017 & 2018: Denounced the Trump administration's strikes against Assad's forces as "illegal and unauthorized.”
February 2019: Voted against a resolution warning President Trump against precipitously withdrawing troops from Syria.