a campaign announcement
... that a U.S. presidential candidate making a campaign announcement is said to "throw one's hat in the ring", after a boxing metaphor popularized by the Theodore Roosevelt 1912 presidential campaign?
... that a U.S. presidential candidate making <b id="mwAsk"><a href="./Presidential_campaign_announcements_in_the_United_States" id="mwAso" rel="mw:WikiLink" title="Presidential campaign announcements in the United States">a campaign announcement</a></b> is said to "throw one's hat in the ring", after a <a href="./Boxing" id="mwAss" rel="mw:WikiLink" title="Boxing">boxing</a> metaphor popularized by the <a href="./Theodore_Roosevelt#Election_of_1912" id="mwAsw" rel="mw:WikiLink" title="Theodore Roosevelt">Theodore Roosevelt 1912 presidential campaign</a>?