President Obama is expected to announce his executive order to grant legal status for millions of illegal immigrants in an address Thursday night, according to sources close to the administration. Mr. Obama will give a broad outline of his action Thursday and follow it up with a trip Friday to Las Vegas to provide more details. The White House would not confirm the report Wednesday morning, nor have Mr. Obama’s aides announced any travel plans for later this week. But a spokesman for the AFL-CIO inadvertently disclosed the tentative plans in an email Wednesday. “We hear there will be a...