As a counteract to the United States Department of State approving a $1.8-billion arms sale to Taiwan last week, Beijing imposed sanctions on US weapons manufacturers, including Lockheed Martin, Boeing Defense and Raytheon, and individuals that have played a "vile role" in the deal on Monday.

Yet this has proved far from enough to deter the US from striking further provocative deals, as the Pentagon approved a $2.37-billion arms sale to the island on Tuesday, the ninth since the incumbent US administration took office in 2016.

The deals not only constitute grave violations of the one-China principle and the three joint communiqués between the US and China, they also directly jeopardize stability in the Taiwan Straits.

The secession-desiring authorities on the island are on a weapons-buying spree because although the Chinese mainland adheres to the strategy of peaceful reunification, it has made clear that it will use force if any attempt is made to separate the island from the motherland.

They are deluding themselves if they think that they will be able to resist the mainland should it come to a military showdown. They should not err in thinking their misplaced pride can subdue the mainland's humility.

Nor should they bank on the US doing more to support their self-aggrandizing objective, despite the US administration's all-round efforts to contain China.

Washington is eager to push Taiwan into a confrontation with the mainland, in the hope that doing so will diminish the latter, but it does not want the US to be dragged into another costly military adventure.

Nonetheless, if the collusion between the island and the US is allowed to continue, the Taiwan question will become entangled ever-deeper into the US agenda, rather than being what it is, China's internal affair.

The relationship between the island and Washington is going through fundamental changes that, if unchecked, will inflict irretrievable harm on China's national interests and sovereignty.

With the gap continuously widening between the Chinese mainland and Taiwan in terms of economic might, if not comprehensive power to transform strategic intentions into realities, building up the island's military strength by cozying up to the US has become one of the few straws the secessionists on the island can hold onto to keep their delusion of gaining "independence" alive.

Since the US administration is willing to indulge them, Beijing has no choice but to continue its war preparedness, and stick to its military modernization. It is predictable therefore that the mainland's sea and air patrols near the island will only become more intensive and regular in the future.

The answer to the Taiwan question is not open to debate.