US senator Ed Markey headed four other US lawmakers and landed in Taiwan on Sunday, an act that left many rational minds scratching their heads.

His visit comes only 12 days after US House of Representatives Speaker Nancy Pelosi visited Taiwan despite strong opposition from both China and those with a clear mind in the US.

It seems that certain US lawmakers are in a competition to show who is tougher with China, and visiting Taiwan is a way of voicing their support to the secessionists there. As mid-term election approaches, they are using China to rally more votes from stoners.

Yet secessionists in Taiwan, namely Tsai Ing-wen and her Democratic Progressive Party, should not take Ed Markey's or any other US lawmaker's trip as "support".

It's a challenge to China's red line and a threat to peace. In response to Pelosi's trip, China launched counter-attacks with military exercises in zones surrounding the Taiwan island, and for every such trip there will be countermeasures.

Neither the secessionists in Taiwan nor their US bosses should underestimate the determination of the central government and 1.4 billion Chinese people to realize national reunification, which will never be stopped by the exceedingly dangerous moves by a few US politicians.

One more Western politician making a trip to Taiwan means moving one step closer to non-peaceful reunification.

Follow the writer on Twitter: @zzxang86