HONG KONG — As dusk settled over Hong Kong, Regina Ip glanced out of the window of her office in the Legislative Council building. Eight floors below, students chanted slogans as they prepared to escalate the boycott that within 48 hours would turn into the most momentous demonstrations on Chinese soil since the Tiananmen protests in Beijing a quarter-century ago.

“We have an identity crisis,” Ms. Ip said in an interview last week. “These young people, they are congregating outside. There’s a lot of problems with them — their sense of identity. How come they cannot identify themselves with China?”