The United States has been proactively influencing politico-economic changes in Hong Kong since the Congress passed the United States-Hong Kong Policy Act in 1992, which is still an important part of Washington's China policy. The US' China policy has not changed much since the two countries established diplomatic relations on Jan 1, 1979, and can be divided into two major phases so far.
Phase 1 began with the establishment of diplomatic ties, especially between Sept 11, 1990, when George H. W. Bush presented the "New World Order" thinking to both the House and Senate of the US Congress, and Dec 18, 2017, when Donald Trump released his first National Security Strategy Report in his capacity as US president. The US government has always maintained a two-pronged China policy of containment and engagement all these years in a bid to "peacefully transform" China, but Washington's global strategy in Phase 1 was focused on Europe and China was not treated as a major competitor to the US.
The principle of Washington's attempts to influence Hong Kong's politico-economic development in Phase 1 was to use Hong Kong as a channel to engage China and as a "Trojan Horse" to facilitate the "peaceful transformation" of China. The Trojan Horse strategy was demonstrated by full-on obstruction of national security legislation according to Article 23 of the Basic Law of the Hong Kong Special Administrative Region by the opposition camp in the second half of 2002, culminating in the mass rally and protest march on July 1, 2003, followed by the illegal "Occupy Central" movement in fall 2014. From the second half of 2003 to the first half of 2015 the opposition camp in Hong Kong went all out in their attempts to force the central government into cloning the Western-style political system in Hong Kong. There were many signs that certain external forces from the US were behind the disruptive activities, which also gave rise to advocacy of "Hong Kong independence". Although such attempts failed to achieve the prime objective, they succeeded in dividing Hong Kong society politically.
When Trump released the National Security Strategy Report on Dec 18, 2017, the US' China policy entered Phase 2. China is now one of the main rivals of the US; while Washington's global strategy shifted its focus to the Asia-Pacific region. In doing so the US government also adjusted its efforts to influence Hong Kong's politico-economic development. Currently it is not yet clear what objective the US' Hong Kong policy aims to achieve next, which means we have to wait and see.
That said, an important signal can be found in the "punitive tariff" hikes on imported steel and aluminum products to 25 percent and 10 percent, respectively, which will not spare Hong Kong even though it is a free port. It is safe to predict that, when the US expands its protectionist offensive on China from goods trade to services trade and particularly the financial market, Hong Kong's services industry and financial market will certainly be affected.
In Hong Kong someone has already put it out there that, since the US-Hong Kong Policy Act allows Washington to differentiate between Hong Kong and the mainland with various preferential treatments, Hong Kong must not let deteriorating China-US relations ruin those preferential treatments, because Hong Kong cannot handle the damage if that happens. That person believes the prerequisite to the US remaining faithful to the US-Hong Kong Policy Act is the Sino-British Joint Declaration on the Question of Hong Kong being followed. In other words, the exercise of "one country, two systems" in the HKSAR must be approved by the US government. This means letting Washington appraise the exercise of "one country, two systems" in Hong Kong and making the SAR a politico-economic instrument of the US government. China will never let the US take control of Hong Kong that way.
The logical conclusion of this scenario is that the HKSAR, as an inalienable part of China, must integrate its own development into the overall development strategy of the country, including joining with the mainland in fighting against US bullying and defeating the latter's containment strategy against China, including Hong Kong. From now on the two political camps in Hong Kong will no longer be determined by whether or not they want "true democracy", which means copying Western political systems, but by who joins the nation in resisting US containment.
So far none of the opposition parties or groups has taken an official standing over the trade war the US government launched on China. That is an intriguing sign to say the least. By advocating "true democracy" the opposition camp seems convinced it has occupied the political moral high ground and its member groups just cannot stop making up their own claims there. If they choose to take the US side over trade disputes with China and support Washington's unilateral and extortionist behavior, it would mean they also support the US strategy to contain China and obstruct the Chinese nation's great rejuvenation. That means they would be seen as betraying the free-trade principle that defines Hong Kong's free port status and would be an enemy of the Chinese nation. Consequently they would lose their moral vantage point altogether.
When it was sworn in on July 1 last year, the fifth-term SAR government could not have foreseen the drastic change of the US global strategy that is unfolding today, and especially not Washington's treatment of Hong Kong through its trade war on China, and the rest of the world. Faced with the fast-changing external situation the SAR government needs to adjust its own administrative approach and policy thinking accordingly.