UK’s Supreme Court says Boris Johnson’s suspension of Parliament was unlawful

Parliament is expected to return to work on Wednesday, as Johnson deals with the still-uncertain political fallout.

The United Kingdom’s Supreme Court has ruled that Boris Johnson’s five-week suspension of Parliament was unlawful, further roiling British politics a month ahead of the Brexit deadline.

In a unanimous decision by 11 justices, the UK’s highest court effectively ruled that Johnson acted illegally when he asked the Queen to prorogue Parliament for five weeks, from early September to October 14.

Johnson had argued that he needed to end one parliamentary session to...