The Trump administration says it will send 2,000 National Guard troops to Los Angeles after two days of isolated clashes between federal immigration agents and protesters.

But sending in the National Guard without a governor’s consent is extremely rare. The most recent comparable example comes from 1965, when President Lyndon Johnson federalised the Alabama National Guard to protect civil-rights marchers from segregationists.

On Saturday, the White House ordered the deployment of the National Guard to Los Angeles to quell protests against immigration raids.