Hong Kong's tentative hold on democracy is in trouble. On Wednesday, four pro-democracy lawmakers — two elected directly by voters and two by unions — were disqualified from the city's legislature over spurious allegations of endangering national security by supporting Hong Kong's independence from mainland China.

After the decision, 15 pro-democracy lawmakers resigned, effectively removing political opposition from Hong Kong's Legislative Council, or LegCo.

Hong Kong's partially democratic parliament is run under the thumb of a "supervisory agency" and dominated by a permanent ruling party supported by Beijing. The territory's "Basic Law" is now being usurped by an alternative constitution, which provides for one-party rule. Things can only go wrong from here.

Read more: China's security law: The end of Hong Kong's semi-autonomous status?

Hong Kong's Basic Law is a set of legal principles based on democratic ideals and the rule of law, which has provided the bedrock for governance in the city since it was handed back to China by the UK in 1997. Until now, these principles have been tolerated by the central government in Beijing.

But Basic Law did not provide for universal suffrage in electing Hong Kong's leadership. Eventually, Hong Kongers demanded more Western-modeled democratic rights from Beijing, including general elections for all parliamentary seats and the head of the city government.

Massive protests were triggered every time Beijing attempted to further restrict democratic principles in Hong Kong. Last year, these protests escalated to a new level of intensity, tempoararily shutting down the city and prompting Beijing to tighten the screws of authoritarianism.

Read more: Opinion: China to rule Hong Kong by fear with new national security law

Using the law against democracy

Hong Kong's legislature, which is packed with Beijing loyalists, recognized they needed to take action and use existing rules in the city's constitution to maintain an authoritarian style of government.

Their strategy was relatively simple. First Hong Kong's Basic Law, which is considered a local law, was introduced into the larger legal framework of the constitution of the People's Republic of China.

This meant officials with China's rubber-stamp parliament, the National People's Congress (NPC), could now intervene in interpreting Hong Kong's Basic Law, expanding Beijing's reach into legal matters in the territory.

Read more: Seeking the right balance for Hong Kong's future

This has happened five times to date, including with this week's decision from Beijing allowing Hong Kong lawmakers to be expelled from the city's legislature, without having the recourse of a court hearing.

The NPC doesn't have to justify its arguments, and the message from Beijing is clear: "We have the final word, and we will only allow the level of democracy that suits us."

Angered Hong Kong judicial officials have said Beijing's behavior is "disrespectful, outrageous and stinks like hell."

Hong Kong law, made in China

It is clear the long arm of Beijing played a role in the expulsion of pro-democracy lawmakers. Although Paragraph 79 of Hong Kong's Basic Law calls for a two-thirds majority vote to disqualify parliamentary deputies, the matter will not be examined by an independent court.

Still, the NPC is the only watchdog behind the scenes. If elected officials in Hong Kong could be indirectly disqualified by a simple decision of the NPC, democracy in Hong Kong would be completely buried.

Critical opinions are essential to a functioning democracy. If Beijing really wanted democracy for Hong Kong, it would have long ago allowed Hong Kongers to freely vote based on public opinions and open criticism.

Read more: China's proposed security law: A death sentence for Hong Kong?

However, Hong Kong's model is an example that partial democracy doesn't work. The founding principle of "one country, two systems" has become a fraudulent claim. When it was introduced, the idea may have been characterized as a courageous and pragmatic experiment within the framework of international law.

Three decades later, Hong Kong's founding principle has turned out to be a tool for power politics from Beijing , which smashes any demand for more democracy and self-rule in the territory.  

One country, two systems was conjured by China's reform-friendly former leader Deng Xiaoping, who wanted to leave Hong Kong alone to govern itself for 50 years. Today, there is clear evidence that the rulers in Beijing have no intention of honoring the founding principle, and Hong Kong's autonomy is hanging by a thread.