Rivals React to Scott Walker’s Surprise Decision

Scott Walker’s now former 2016 rivals praised the Wisconsin governor following his announcement suspending his presidential bid, while some GOP political operatives expressed surprise over the one-time frontrunner’s decision.

South Carolina Sen. Lindsey Graham, who said he was caught off guard by Walker’s announcement, attributed the decision to Donald Trump’s rise and a crowded field of Republican presidential candidates.

“The one thing I can tell you: When you rise and fall it’s tough. You know, once you start falling it’s probably tough to regain your footing in a field this big,” Graham said. “I think a lot of it is Trump, nobody saw that one coming, but it’s just a lot of people out there.”

Wisconsin Governor Scott Walker Drops Out of GOP Presidential Race 1:56

News of the end of Walker’s campaign came during an online forum featuring many of the GOP presidential campaign managers held by Google, YouTube and the National Review.

“I’m surprised. I think a lesson that a lot of folks learned from [2012 presidential candidate Tim] Pawlenty getting out too early last time was that, you know, don’t give up, you’re going to hit rough spots, ” said Ben Carson's campaign manager, Barry Bennett.

Marco Rubio's campaign manager, Terry Sullivan, said, however, he was “not shocked” by Walker’s decision, given signs that the campaign had run into fundraising troubles.

Walker was the early frontrunner among 2016 Republicans, but a series of missteps and the rise of Donald Trump ultimately doomed Walker, forcing him to leave the race much earlier than most expected.

When announcing the end of his presidential bid, Walker said he was leaving the race so that voters could focus on finding "a positive, conservative alternative to the current frontrunner."

That continues to be Trump, whose lead has shrunk but is still in place following the second Republican presidential debate. Before Walker spoke, Trump tweeted his praise for Walker, who he at times clashed with during the campaign.

"Scott Walker is a good man who entered the presidential race after winning three grueling campaigns in four years,” Rubio said in a statement, referring to Walker’s three gubernatorial victories. “I know many people are disappointed with Scott's announcement and I respect what a difficult decision it must have been.”

Ted Cruz said, “Gov. Scott Walker is a good man, a formidable fighter, and an effective reformer....In the presidential race, his focus on new, innovative policy ideas made the entire Republican field better.”

Many others in the crowded GOP field also spoke highly of Walker on twitter:

NBC's Frank Thorp V contributed to this report.