Over 1,200 enthusiastic Iowans filled a Cedar Rapids convention center Saturday morning in support of Bernie Sanders, the grassroots presidential candidate making a final, aggressive push ahead of Monday's pivotal caucus.

"A great turnout means we retain the White House, we regain the Senate, we elect governors all over this country," Sanders said. "We are going to expose like they have never seen before the right wing reactionary Republican agenda."

Sanders spent a majority of the speech rebuking Democratic front-runner Hillary Clinton's strategy, specifically commercials insinuating that he opposes funding for Planned Parenthood and supports the NRA.

Drawing a contrast between his and the former New York senator's finances, Sanders made a point of reminding Iowans that Clinton's campaign relies on Super PACs, whereas his doesn't.

"In the general election campaign there is going to be a very clear choice. One of us is going to be on the side of the middle class and working families. One of us is going to be standing up for seniors and our veterans," Sanders said.

Among the campaign surrogates joining Sanders onstage Saturday were former Illinois Sen. Chuy Garcia and Arizona Congressman Raul Grijalva. The Latino politicians hosted a series of events urging Iowa Latinos to participate in the caucus process on Feb. 1.

Progressives on Parade: Chuy Garcia, Raul Grijalva, Cornel West, Keith Ellison to introduce Bernie in Cedar Rapids pic.twitter.com/3ry5OdwGKC — Sam Frizell (@Sam_Frizell) January 31, 2016

They delivered a similar message in Cedar Rapids, telling attendees that Sanders is the candidate best suited to deal with the country's most pertinent issues, including health care and climate change.

Grijalva appealed to Sanders' record as a democratic socialist, saying people are sick and tired of the concentration of power and money going to the rich; many who still worry about how to pay ever-rising school and health care costs.

"[People are] tired of carrying the burden, so the scraps off the table - after corporate America, the billionaire class, and the one-percent are done - the scraps of opportunity, the scraps of jobs, the scraps of democracy fall off the table," Grijalva said. "Bernie Sanders gives us an opportunity to flip that table over."

Garcia compared Sanders' campaign to President Obama's initial run in 2008, saying both were told they could never be president.

"Just like Iowa show what was possible in 2008, I think Iowans are ready what is possible in 2016," Garcia said. "Regardless of where we come from - from rural parts of Iowa, from the cities in Iowa, or from the Windy City in Illinois - we know that change is possible."

Garcia said the "best vessel" for real transformative politics, regardless of race or income bracket, is in Sanders.

The final Des Moines Register/ Bloomberg poll released Saturday night showed Sanders trails Clinton by a slim three-point margin. Clinton is the top pick for 45 percent of likely Democratic caucus-goers while 42 percent said they support the Vermont senator.

Four-in-five respondents firmly behind one Democrat said they won't consider voting for the other leading candidate. Nine percent said they are still undecided while 30 percent said they can still change their mind.