Why has the relationship between the Chinese mainland and Taiwan taken a turn for the worse?

Relations between the Chinese mainland and Taiwan have steadily grown more tense since 2016 when Tsai Ing-wen from the Taiwanese independence-leaning Democratic Progressive Party became the self-ruled island’s president. Cross-strait tensions have only intensified since her re-election in January 2020, and because of a hardened US stance toward Beijing that has seen Washington step up its support for Taipei. News of American proposals to sell more advanced weaponry to Taiwan has been countered…