BRUSSELS—The European Union must stand with Lithuania against Chinese pressure and not give in to trade threats, Slovenia’s prime minister said in a letter to fellow EU leaders, according to a copy seen by Reuters. The Chinese regime’s decision to withdraw its ambassador to Lithuania over a dispute about Taiwan was “reprehensible” and would hurt EU-China ties, Slovenian Prime Minister Janez Jansa, whose country holds the six-month EU presidency, said in his Sept. 13 letter. “We will be able to face China successfully only with a united, coherent, and common approach,” Jansa wrote. “We must stand by every EU member state that is facing pressure.” Lithuania and Taiwan this year opened reciprocal representative offices in a sign of deepening relations. The Chinese communist regime considers fiercely democratic, self-ruled Taiwan as part of its territory and has threatened to use force to bring the island under its control. It’s regularly angered …