The 19-year-old supported the 'End the war on drugs' and has encouraged his followers on Twitter to support the cause, reported Aceshowbiz.
"I'm going to always keep encouraging people to move in the right direction," Bieber re-tweeted a message written by Russell Simmons who posted an open letter to the President. "Shoutout to @UncleRUSH.
Gotta support him to #EndTheWarOnDrugs and show that we the youth have a voice. hashtag and support the cause," he added. Simmons urges in his letter to "revamp the policies of the last 30 years that have seen the prison population skyrocket."
"The greatest victims of the prison industrial complex are our nation's children. Hundreds of thousands of children have lost a parent to long prison sentences for non-violent drug offenses, leaving these children to fend for themselves," he says.
He urges the government to implement "more alternatives to incarceration" and to support "the Youth Prison Reduction through Opportunities, Mentoring, Intervention, Support, and Education (Youth PROMISE) Act."
The letter has been co-signed by Smith, Johansson, Diaz, Jon Hamm, Russell Brand, Susan Sarandon, Tim Robbins, Demi Moore, Mark Wahlberg, Eva Longoria, Woody Harrelson, Jamie Foxx, Jim Carrey and Kerry Washington.
Photos: Raveena Tandon, Sohail Khan at Marathi film 'Bhay' music launch
SRK-Gauri anniversary: B-Town stars and their non-filmi better halves
Birthday special: Popular mothers and daughters in Bollywood
Spotted: 'Kaabil' star Hrithik Roshan with dad Rakesh Roshan
'Rock On 2' trailer launch: Farhan, Shraddha enthrall audience with live gig