CLEVELAND — Donald Trump’s campaign on Wednesday embraced the thematic “lock her up” line of attack on Hillary Clinton that has taken hold during the Republican convention.

“Lock her up” wasn’t an official talking point of the Republican nominee’s campaign, appearing to bubble up organically amid the deliberate focus on Clinton’s use of a private email server during her tenure as secretary of state that FBI Director James Comey said came close to breaking the law and endangered national secrets.