To show one's political support for someone or something. If the incumbent president announces for me, it will be a huge boost to my campaign.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
announce (one's support) for someone or something
to declare one's political support for someone or something. The senator announced for the Supreme Court nominee. Our club announced for the incumbent candidate.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.