U.S. House Speaker Nancy Pelosi’s Taiwan trip was only the most high-profile in a series of moves by Congress that are forcing U.S. President Joe Biden to test Beijing’s red lines — whether he wants to or not.

Pelosi’s visit, the first by a sitting speaker in a quarter century, was the most senior in a wave of congressional delegations to travel to Taipei. At least 149 U.S. senators and representatives have made trips to the democratically governed island over the past decade, according to Taiwanese government statements and congressional travel records, including 33 so far under Biden.

On Sunday, Sen. Ed Markey, a Massachusetts Democrat, arrived in Taiwan as part of a five-member congressional group, making this year the busiest for such visits since 2016. The Chinese military announced fresh military patrols in the "sea and air space around Taiwan” on Monday to "fight back” against Markey’s visit.