I was tortured in a Chinese prison. Now I'm marching for freedom.

Silence is golden, goes the aphorism. But consider the 1936 Olympics in Nazi Germany. Instead of walking away from the Olympics, which would have removed any tacit approval of Hitler, leaving him less emboldened – possibly even changing the course of history – the world was silent.

We stir up trouble by speaking out.

But I am speaking out. Because the people inside China cannot speak out, and because thousands of brothers and sisters in prison need a voice.

I served five years as a political prisoner in China, from which I was released only last year. I was tortured, both physically and psychologically, and put in solitary confinement for the first 14 months. I was charged with "espionage," a crime of which I was innocent, and one that can mean jail for life or result in the death sentence.

My family hired a prominent Chinese lawyer in February 2003, after I had been detained. But it was only after the US House and Senate adopted resolutions calling for my release in June 2003 that I was finally allowed to meet with this lawyer.

The pressure from the US eventually made a great difference in my prison experience – I was given more freedom within the prison, and no longer tortured. The fact is that without the leadership of the US, I might never have been freed.

Even when I was finally released from prison, the Chinese government kept me in China, preventing me from uniting with my family in America. If it were not for Congressman Barney Frank and Treasury Secretary Henry Paulson working on my behalf, I would not have been able to come home in August 2007.

I am just one man. But I know I need to speak out for the thousands of political prisoners languishing in jail without hope and support, including dozens still serving time for the Tiananmen Square student democracy movement in 1989; for those lawyers seeking to gain human and civil rights for their clients, for those prohibited from practicing their religion, and for those who are afraid to speak out because of the grave consequences consistently doled out by the Chinese government. I need to speak out for the invisible – the abducted, or those placed under house arrest for no other reason than for attempting to exercise their basic human rights.

So on May 4, I began walking 500 miles. It should take over 32 days to make my way from Boston to Washington, DC. I am calling my walk GongMin, which means "Citizen" in Chinese. I'm walking for "citizen power" in China. I'll walk through Providence, New Haven, Bridgeport, New York, Philadelphia, Wilmington, and Baltimore. My walk will conclude on June 4, the 19th anniversary of the Tiananmen Square Massacre, where there will be a large gathering and remembrance in Washington.

I'm walking 500 miles as a free man, to draw attention to the struggle for freedom and democracy of Han Chinese, Tibetans, Uighurs, Mongolians, and people of all ethnic groups. And I'm walking to call for the US to continue its moral leadership.

The best option is for the US to continue to pressure China to enter a dialogue with human rights advocates around the world.

Human rights are what this great country was founded upon – they cannot, and should not, be commodified or weighed on a scale of pros and cons.

Silence, in this case, is not golden. Silence, as in the 1936 Olympics in Nazi Germany, is deadly.

• Dr. Yang Jianli is founder of Initiatives for China, dedicated to empowering the citizens of China by giving voice to their struggles for a peaceful transition to democratic China. He is a former political prisoner in China.