Speaking to voters at a town hall meeting in Rock Hill, South Carolina over the weekend, Republican presidential hopeful Sen. Marco Rubio defended his controversial "Gang of Eight" immigration reform bill.

The Florida senator explained to a room of supporters that the bill, which ended up passing, was not actually intended to be the final written draft of the law President Barack Obama would eventually sign.

The so-called “Gang of Eight” bill, or S. 744, was a bi-partisan proposal intended to reform the U.S. immigration system.

The landmark legislation was written by a Sens. Charles Schumer, D-N.Y., John McCain, R-A.Z., Richard Durbin, D-I.L., Lindsey Graham, R-S.C., Robert Menendez, D-N.J., Marco Rubio, R-F.L., Michael Bennet, D-C.O., and Jeff Flake, R-A.Z.

The Best Bill They Could Write

The bill arguably offered amnesty to undocumented migrants living in the United States by making changes to the family and employment-based visa categories and providing essential due process protections to undocumented migrants.

In order to pursue eventual citizenship, undocumented immigrants -- who had been in the U.S. before Dec. 31, 2011 -- would have to first apply for “registered provisional immigrant” (RPI) status. This would allow them to live and work in the U.S. for six years. This application would require a $1,000 payment and a background check. After six years, immigrants would need to pass another background check and then meet certain work or educational requirements in order to renew their RPI status.

Immigrants who came to the U.S. before the age of 16 and received a high school diploma or a GED could get green cards after five years of RPI status. These younger applicants would not have to pay the $1,000 fine, but would need to finish two years of college or four years of military service, and pass a background check, as well as English and civics tests.

Overall, conservatives liked the background checks and the nearly 40,000 Border Patrol agents that would have been deployed to the border under the new bill. Liberals liked the allowances made for young adults who fell under the DREAM Act.

“The Senate immigration law was not headed toward becoming law,” said Rubio. “Ideally it was headed towards the House where conservative members of the House were going to make it even better.”

Rubio described the bill as the best option available at the time, given the senatorial circumstances the legislators faced.

Cruz Condemns Bill

Fellow 2016 GOP presidential candidate Sen. Ted Cruz voiced his opposition to the problems he saw with the bill at the time. Speaking to Fox News, Cruz complained the bill was just repeating a failed pattern of offering amnesty.

“In 1986 congress came to the American people and said we’re going to grant amnesty to some 3 million people who are here illegally, and in exchange we’ll secure the borders, we’ll fix the problem so illegal immigration will go away. What happened was the amnesty happened, 3 million people got amnesty, but the border never got secured,” Cruz said.

The senator went so far as to introduce an amendment that would allow for undocumented immigrants to gain legal status so long as they were never allowed to become citizens with the right to vote. As the National Review reports, Cruz’s amendment would have also increased border security by tripling the number of agents and quadrupling the amount of surveillance equipment. He also suggested implementing a biometric entry-exit system at border crossings.

A Bill Based on Compromise

The Border Security, Economic Opportunity, and Immigration Modernization Act relied heavily upon the cooperation and compromise of Democrats and Republicans in the Senate.

Schumer described the bill as a kind of meeting ground where left and right-leaning legislators could meet on one vital issue.

"We all met in the middle, knowing we would not please our entire constituencies, but the imperative of doing this is so important to the country that we had to get it done," Schumer said, according to U.S. News and World.

Rubio, who had spent a great deal of time trying to persuade his fellow Republican legislators to favor the bill, said he voiced his complaints on what he considered weaknesses in the bill after it passed the Senate. Rubio was known as the Gang’s official ambassador to the conservatives, as he was welcomed by conservative media.

As the New Yorker reports, Durbin called Rubio's promotion of the bill invaluable.

“He’s willing to go on the most conservative talk shows, television and radio, Rush Limbaugh and the rest,” said Durbin.

Rubio described the "Gang of Eight" bill as a starting point, which would be expanded upon once he was elected president.

“When I’m president, we’re not doing anything until illegal immigration is under control and we’ve secured our border,” Rubio said. “And until that happens, nothing else is going to happen. Period.”

Watch Rubio's comments on the bill: