Scott Walker
U.S. Republican presidential candidate and Wisconsin Governor Scott Walker waves as he is announced during the Heritage Action for America presidential candidate forum in Greenville, South Carolina September 18, 2015.REUTERS/Chris Keane

Republican presidential candidate Scott Walker suspended his bid for the GOP nomination to "clear the field" and make it easier for voters to choose their candidates. Walker, the governor of Wisconsin, made his campaign-ending announcement in Madison on 21 September.

"Today, I believe that I'm being called to lead by helping to clear the field in this race for a positive conservative message to ride to the top of the field," Walker told reporters during the press conference. The announcement follows a new CNN poll which placed Walker as earning less than 1% support from voters.

Walker, who had a promising campaign, was hurt by his two weak performances during the GOP debates in August and earlier in September. According to Politico, his decision to step down has opened up opportunities for candidates, such as Marco Rubio, to grab some of his financial donors.

According to an unnamed source, Walker held private meetings on 21 September before his big announcement. Walker reportedly said "finances just aren't there" to a group of staffers, adding that the "field needs to narrow to a positive conservative messenger."

Ron Kaufman, a Massachusetts operative backing GOP candidate Jeb Bush told Politico that one of the biggest mistakes the Walker campaign made was failing to meet expectations after a big start. "In terms of how the press and voters view these candidates, the bar is different for everybody," he said. "The bar forJeb is so high because you all see him as president. Trump's bar is very low. Walker was fine in the beginning because his bar was low. As soon as he said: 'I'm the front-runner,' the bar went way up and he couldn't get over it."

Another advisor backing Bush's presidential campaign, former Minnesota congressman Vin Weber told the The Washington Post: "It was nice for him to get that attention in the short run, but it sets up expectations he couldn't hope to maintain."

In a statement to the Post, union leadership reacted to Walker's departure from the campaign. Walker has long made a name for himself as being anti-union. "Scott Walker is still a disgrace, just no longer national," AFL-CIO president Richard Trumka said.

Some have placed the blame for his campaign's demise on his group of aides. According to the Post, Trump wondered if Walker was hurt by too many consultants handing out too much advice. "He was a very loose guy when he came up to see me a few months ago to give me a plaque, but then on the campaign, maybe there were too many people. I think he had too many people, many of them who didn't know what they were doing."