Jon Huntsman Jr. announced Monday morning the end to his presidential candidacy and his immediate endorsement of Mitt Romney at a press conference in Myrtle Beach, S.C.

"Former Utah governor Jon Huntsman abandoned his quest for the presidency Monday morning with an endorsement of former Massachusetts governor Mitt Romney and an unexpectedly sharp condemnation of the 'toxic' tone that the Republican primary battle has taken," the Washington Post reports. "'This race has degenerated into an onslaught of negative and personal attacks not worthy of the American people and not worthy of this critical time in American history,' Huntsman said in a news conference in which he was flanked by his wife, children, father and South Carolina supporters."

Politico's Maggie Haberman weighed in that the announcement served as an "unusual press conference" because of Romney's glaring absence (announcements of this magnitude usually attract the endorsee's presence).

Romney's campaign released the following statement: "I salute Jon Huntsman and his wife Mary Kaye. Jon ran a spirited campaign based on unity not division, and love of country. I appreciate his friendship and support."

Haberman writes, "This statement underscores many things — the lack of love between the two men, the hostility that existed between them at the debates, and, most significantly, the extent to which Huntsman's bow-out and endorsement doesn't seem to be part of an operatic coordination between the two campaigns."

If Romney isn't already in Myrtle Beach, he soon will be given his scheduled appearance at Monday night's GOP presidential debate.

The Washington Post detailed in early 2011 that Huntsman and Romney have endured a rocky relationship since before their governorships, dating back at least to when Romney was tabbed to be the CEO of the 2002 Salt Lake City Olympics.