As senator, his voting record was measured as the third most liberal. Considered a social liberal, Booker supports women's rights, affirmative action, same-sex marriage and single-payer healthcare. During his five years in office, Booker co-sponsored and voted for the Employment Non-Discrimination Act (2013), tougher sanctions against Iran, sponsored the Bipartisan Budget Act (2013), voted for the National Defense Authorization Act (2014), co-sponsored the Respect for Marriage Act (2014) and led the push to pass the First Step Act (2018). In 2017, he became the first sitting senator to testify against another when he testified against Attorney General nominee Jeff Sessions during his confirmation hearing. In April 2018, following the FBI raid on the offices of Michael Cohen–U. S. President Donald Trump's personal attorney–Booker together with Chris Coons, Lindsey Graham, and Thom Tillis, introduced the Special Counsel Independence and Integrity Act to limit the executive powers of Trump.