He suspended his campaign on January 13, 2020, later endorsing former Vice President Joe Biden, who went on to win the Democratic nomination and the general election.

Along with Senators Harris, Gillibrand, Warren and Sanders, he had voted overwhelmingly against Trump nominees for administration jobs.

He has also expressed support for medical marijuana research,[30] decriminalizing marijuana, ending mandatory minimum sentences for non-violent drug offenders, increasing funding for prisoner re-entry programs, and bringing an end to for-profit, private prisons.

[33][34] In June 2018, Booker joined with Sen. Kamala Harris (D-California) and Sen. Tim Scott (R-South Carolina) to introduce a bill to make lynching a federal hate crime.

Booker has publicly defended the right of law-abiding citizens to own legal fire arms and blames most shootings on criminals with illegal guns.

[44][45][46][47][48][49][50] Booker advanced his position in the same month, ... House of Representatives ... finally passed the "background check bill"[51] which is due to a lot of activism, a lot of struggle ... this was a bipartisan bill as well ... over 95% of Americans believe in common sense comprehensive background checks ... We have got to get this done[52][non-primary source needed]In May 2012, Booker defended Bain Capital's record and criticized Obama's attack on private equity.

[53] Booker is in favor of creating so-called "baby bonds", whereby newborns would be given low-risk savings accounts (managed by the Treasury) that would be worth tens of thousands of dollars by the age of 18.

[54] According to an analysis by Naomi Zwede of the Center on Social Policy and poverty at Columbia University, the baby bonds would almost entirely close the racial wealth gap among young people.

[56] Speaking to Newark airport workers in May 2017 he said, "It is un-American to be in this country, to work a full-time job and still live in poverty.

[58] Booker wants to see the tech sector reach its fullest potential, and to do that, he thinks the U.S. government needs to ease up on regulations.

[59] In stark contrast to Warren and Sanders, Booker invites Amazon to set up a major office (nicknamed "HQ2") in Newark, New Jersey.

[63][64] Booker backs the scientific consensus on global warming that it is man-made and is in favor of cap-and-trade or a carbon tax for reducing greenhouse gas emissions.

[66]In September 2018, Booker was 1 of 8 senators (along with Harris) to cosponsor the Climate Risk Disclosure Act, a bill described by Warren as using "market forces to speed up the transition from fossil fuels to cleaner energy — reducing the odds of an environmental and financial disaster without spending a dime of taxpayer money.

The resolution affirmed the senators' acceptance of the findings and their support for bold action toward addressing climate change.

[81] In October 2018, Booker was 1 of 20 senators to sign a letter to Secretary of State Mike Pompeo urging him to reverse the rolling back of a policy that granted visas to same-sex partners of LGBT diplomats who had unions which were not recognized by their home countries, writing that too many places around the world have seen LGBT individuals "subjected to discrimination and unspeakable violence, and receive little or no protection from the law or local authorities" and that the US refusing to let LGBT diplomats bring their partners to the US would be equivalent of America upholding "the discriminatory policies of many countries around the world.

[84] Regarding immigration detention, a joint letter dated June 2015 by 33 senators (including Gillibrand, Warren, and Sanders) criticized that as "unacceptable and goes against our most fundamental values".

[85] In July 2018, Booker was among 11 senators to sign a letter requesting the agencies responsible for reuniting families provide weekly updates, until every separated child was returned to their parents, in the form of a list of separated children, a list of their parents and other adult members of their families in addition to a list connecting the lists of children and parents and a briefing for the lawmakers on the strategies used to reunite families,[86] and was 1 of 22 senators to sponsor the Stop Shackling and Detaining Pregnant Women Act, which if enacted would prohibit immigration officers from detaining pregnant women in a majority of circumstances and improve conditions of care for individuals in custody.

[87] In January 2019, Booker was 1 of 21 senators to sponsor the Dreamer Confidentiality Act, a bill imposing a ban on the DHS from passing information collected on DACA recipients to ICE, CBP, the DOJ, or any other law enforcement agency with exceptions in the case of fraudulent claims, national security issues, or non-immigration related felonies being investigated.