Landmark national security trial of Hong Kong democracy activists begins. Here's what you need to know

Police stand guard outside the West Kowloon Magistrates' courts in Hong Kong on November 25, 2022.

Hong Kong (CNN)Some were seasoned politicians and veteran protest leaders. Others were academics, unionists and health care workers. They hailed from different generations and held a range of political views, but were brought together by what they say was a shared commitment to Hong Kong's democratic future.

Now, the "Hong Kong 47," as the group of pro-democracy activists in the semi-autonomous Chinese territory has come to be known, will start appearing in court from Monday facing charges that could send them to prison for life.
Sixteen of the defendants have pleaded not guilty to the charges laid against them and are expected to be the first ones to take the stand.
    Their alleged crime? Organizing and participating in an unofficial primary election that prosecutors have called a "massive and well-organized scheme to subvert the Hong Kong government."
      This is Hong Kong's largest national security law trial since Beijing imposed the sweeping legislation on the city following mass anti-government protests in 2019. The law criminalizes vaguely defined acts of secession, subversion, terrorism, and collusion with foreign forces, all of which are punishable by life in prison.
      The landmark trial -- the first involving subversion charges -- is expected to run for weeks, but its implications could last for years or even decades in a city critics say is rapidly losing its political freedoms and autonomy.
      John Burns, emeritus professor at the University of Hong Kong, said the trial of the democrats is a "test of will" of Beijing's capacity to completely wipe out organized opposition in Hong Kong.
        Burns said arresting the democrats and pressing charges against them was meant to both intimidate and eliminate the opposition, either by chasing them out of Hong Kong into exile or by jailing them.
        "It is a process of removing them. By shutting down political parties, shutting down trade unions, they are shutting down the basis of the support for organized opposition," Burns said.