Updated 10:40 a.m. Sunday

Sen. Charles E. Schumer (D-N.Y.) on Saturday became the most senior Democratic lawmaker yet to call on Hillary Rodham Clinton to run for president in 2016, calling her the best-prepared to "vanquish" tea party Republicans in the next election.

Sen. Charles E. Schumer  (J. Scott Applewhite/AP)

Election Day 2016 is still more than three years away, and Clinton isn't expected to make a final decision on whether to run for president until next year. But that didn't stop Schumer, the third-ranking Senate Democrat, from using a rare visit to Iowa to do some early campaigning on behalf of his former Senate colleague from New York. "I am urging Hillary Clinton to run for president, and when she does, she will have my full and unwavering support," he said Saturday evening during a keynote address to an Iowa Democratic Party fundraiser in Des Moines.

"Run, Hillary, Run," Schumer's prepared remarks said. "If you run, you’ll win, and we’ll all win."

Schumer went on to say: "With a strong platform and with Hillary leading the charge, we will vanquish the Ted Cruz, Tea Party Republicans in 2016 and create a generation of Democrats who will make sure the middle class gets what it needs, our country advances and the torch held by that beautiful lady in New York’s harbor burns more brightly than ever."

Aides to Schumer alerted reporters to his intentions ahead of the speech and provided excerpts of his prepared remarks. Just before he gave the address, Schumer also made his intentions known via Twitter:

Clinton spokesman Nick Merrill said Sunday that Schumer's endorsement was "very flattering," but that Clinton has not decided whether to run for president.

"Senator Schumer is an old colleague and an even older friend, and what he said about her is very flattering," Merrill said. "Ultimately though this is a very personal decision that she hasn't made."

The early endorsement could cause political trouble for Schumer if Clinton backs out of a campaign or ever falls behind another, as-yet unknown Democratic challenger. But the announcement appeared designed in part to begin consolidating Democratic support behind Clinton. And it will be seen as another setback for Vice President Biden, another of Schumer's former Senate colleagues who has not yet ruled out running for president, and who recently phoned a newly-elected Democratic state senator in Iowa to congratulate him on winning a special election.

A new book about the 2012 presidential campaign set for release this week recounts how some top advisers to President Obama contemplated replacing Biden on the 2012 ticket with Clinton and how Biden tried to arrange meetings with Silicon Valley heavyweights last year in hopes of securing their financial support for a future campaign.

Schumer is by no means the first Democratic lawmaker to formally endorse and encourage Clinton's campaign. News reports last week revealed that all of the female Democratic senators signed a secret letter to Clinton earlier this year encouraging her to run and that several of them -- including Sens. Claire McCaskill (Mo.), Kirsten Gillibrand (N.Y.) and Barbara Boxer (Calif.) -- regularly tout her potential campaign.

As New York's senior senator, Schumer backed Clinton's 2008 bid for president when she was still serving as the junior senator from New York. On Saturday night, Schumer said that in 2008 "the time was right for Barack Obama" but then added that "2016 is Hillary's time."

Philip Rucker contributed this story.

Follow Ed O'Keefe on Twitter: @edatpost