Republican presidential candidate Marco Rubio is now viewing the much debated immigration issue as more of an issue of national security as opposed to a question of what to do with millions of illegal immigrants in the country. The presidential candidate has evolved in his stance on the topic, which has caused many heated debates with conservative voters.

Rubio said that the concept of immigration has now drastically changed. In a speech that he gave to voters in New Hampshire, he said that radical jihadist groups were using the country's immigration policies against them, and that this is a very pressing issue that can no longer be ignored.

In a report with Fox News Latino, Rubio struggles to explain his supporting an immigration overhaul bill that included a path to citizenship in the past.

One of Rubio's chief rivals, Ted Cruz, has criticized Rubio in the past for being too soft on the issue of immigration. The question of immigration is often presented by many skeptical voters during political campaigns, who believe that Rubio is undecided on the issue.

With Rubio's backing, the immigration overhaul bill passed the Senate, but he later backed off the proposal, as it drew much criticism from the conservative right. When asked for his explanation on doing so, Rubio said he favors a "one-piece-at-a-time approach."

Rubio believes that the federal government needs to boost border security. The Republican presidential hopeful hopes to modernize the legal immigration system. He adds that the government should improve tracking those immigrants with overstay visas. Rubio believes that the e-verify system should be made mandatory.

The presidential hopeful has recently started the immigration segment of his speech by showing deficiencies in the U.S.-Mexico border. He views the existing legal immigration system as a national security threat.

Rubio has also warned voters that the Islamic State group is recruiting fighters to send to the United States, having them pose as civilians, such as doctors, students and investors.

Yahoo reports that Rubio says if the U.S. government cannot establish the identity of a person coming into the United States, they won't be allowed in under his administration.

However, Rubio's views on immigration has long been seen as evolving.

In 2008, Rubio was criticized by his GOP colleagues for not bringing in several bills that were aimed at discouraging illegal immigrants to vote. These bills reported to include employer verification requirements. One bill also proposed to require police to report people suspected of being in the country illegally.

Rubio's views began to shift rightward when he ran for a spot in the Senate in 2010, where he was instantly a favorite. He promised to oppose any legislation that would grant amnesty to illegal immigrants.