Hillary Clinton and Marco Rubio Pick Up Coveted Iowa Newspaper Endorsement

Clinton faces a tight race against Sanders, and Rubio is behind Trump and Cruz.

"Democrats have one outstanding candidate deserving of their support: Hillary Clinton," reads the endorsement for the former secretary of state. "No other candidate can match the depth or breadth of her knowledge and experience."

The endorsement was not without caveats, however.

"She is not a perfect candidate, as evidenced the way she has handled the furor over her private email server," the editorial board writes.

"Sen. Marco Rubio has the potential to chart a new direction for the party, and perhaps the nation, with his message of restoring the American dream," the endorsement reads. "We endorse him because he represents his party’s best hope."

Clinton was working the rope line at her "Hard Hats for Hillary" event in Davenport, Iowa, just as her endorsement by the Des Moines Register was announced.

"I'm very pleased, obviously," she told reporters. "It means a lot."

ABC News' Liz Kreutz and Josh Haskell contributed to this report.