Former Minnesota Gov. Tim Pawlenty sent an email to supporters Sunday with video that previews his formal campaign announcement, set for Monday.

"We need a President who will tell the American people the truth about the severe challenges facing our nation and how we can get America back on track," Pawlenty's email said. "President Obama won't do that. I will."

In a Web video sent with the email, the Republican candidate continued on his theme of truth-telling.

"I could promise that we could eliminate a $14 trillion debt, create jobs for ten million people, restructure Social Security and healthcare all without making any tough decisions — or I could try something different: I could just tell you the truth," Pawlenty says over waving flags and soft music in the video. "The truth is our country's in big trouble."

The ex-governor also published an op-ed in the USA Today previewing his message, and appeared on CBS's "Early Show," ABC's "Good Morning America" and NBC's "Today Show."

"Conventional political wisdom says that it's better to tell people what they want to hear, rather than what they need to hear," he wrote in USA Today. "But conventional political wisdom is what got us into this fiscal mess in the first place. Anyone who can't tell hard truths now won't be able to lead our country in the future. We now know that President's Obama's promise of 'hope and change' was just hopeless hype."

Pawlenty is joining a wide-open Republican field for the 2012 nomination.

On Sunday morning, Indiana Gov. Mitch Daniels spread the word that he would not join the race. Former Arkansas Gov. Mike Huckabee said on his Fox News show a week ago that he wasn't going to run and real estate mogul Donald TrumpDonald John TrumpTrump and Kim fight PR war as summit talks collapse Trump appears to confirm deal on Chinese firm ZTE Judge rejects Manafort's attempt to throw out some charges MORE has opted out as well.

Former House Speaker Newt Gingrich and former Massachusetts Gov. Mitt Romney are in the hunt, but both have had rocky starts to their campaigns. Businessman and radio host Herman Cain announced on Saturday that he was joining the field.

Marquee names, such as former Alaska Gov. Sarah Palin and Rep. Michele BachmannMichele Marie BachmannBachmann won't run for Franken's Senate seat because she did not hear a 'call from God' Billboard from ‘God’ tells Michele Bachmann not to run for Senate Pawlenty opts out of Senate run in Minnesota MORE of Minnesota, haven't announced their intentions yet.

A CNN poll from May 5 found Pawlenty ranked near the bottom of the list in terms of support. Three percent of Republicans sampled said he would be their first or second choice. Huckabee and Romney tied for first in that category, with 18 percent support each.

—This post was updated at 7:16 a.m.