Immigration has become a highly debated topic among Republican presidential candidates. Most have advocated for securing the U.S.-Mexico border first, and then working at immigration reform, according to the Washington Post. Most candidates have taken conservative positions and those who haven’t have become targets.

When Republicans were asked in February what issues were most important to them, immigration was seventh. In a poll taken this week, immigration was fourth, according to NPR. It was behind only energy and the two wars.

Here is some information about some of the candidates’ ideas on immigration:

Herman Cain

Cain said he would build an electric fence at the U.S.-Mexico border that could kill people who cross illegally at a rally in Tennessee, according to the N.Y. Times.

Cain also said he would consider using military troops to stop intruders.

During a later interview with “Meet the Press” with David Gregory, Cain said that he was joking about having a lethal fence, according to the Washington Post.

Cain has been advocating for a fence that some have compared to the Great Wall of China.

Michele Bachmann

Bachmann said that she would build a “secure double fence” and eliminate “taxpayer-funded benefits for illegal aliens,” at an event in Perry, Iowa, reports the N.Y. Times.

Bachmann referred to illegal immigration as an economic and security threat.

On Saturday, she signed the Americans for Securing the Border pledge to construct the fence by the end of 2013, according to ABC News.

Bachmann said the fence will be “job number one” if elected and that illegal immigration costs the U.S. $1 billion a year.

Rick Perry

Perry has taken a no-border-fence stance and is in favor of in-state tuition for illegal immigrant students.

Perry has received some heat from Bachmann over immigration policies he advocated in Texas. In 2001 Perry signed a law that allowed undocumented students who graduate from a Texas high school to attend a state college for in-state tuition. Bachmann said this violates 1998 federal law, according to the N.Y. Times.

Perry has also supported a Texas-style DREAM Act, according to the Washington Post.

During his time as governor of Texas, Perry opposed immigration policies popular with conservatives, which may now hurt him. He has said that building a fence with Mexico was “preposterous” and “an idiocy,” Politico reports. He supported a guest worker program for immigrant labor and does not support Arizona-style immigration laws.

Perry has since stressed border security, but not immigration reform, according to Politico. Still, Perry has not taken a hard stance against immigration which could hurt him with conservatives, but take away some Hispanic votes from Democrats.

Mitt Romney

Romney referred to illegal immigrants as illegal aliens during a debate, according to the Washington Post.

Romney has taken a hard stance against immigration, which has had positive results with conservative voters. It could, however, antagonize Nevada’s growing Hispanic population. Nevada is expected to be a key swing state in the general election, Politico reports.

Romney said at a town hall meeting in Salem, New Hampshire earlier this month that he supports a border fence, English immersion in schools, a crackdown on employers of illegal immigrants and denying welfare benefits to illegal immigrants, the United Press International reports.

He has also opposed giving children of illegal immigrants in-state tuition.

Newt Gingrich

Gingrich does more Latino outreach then any of the other candidate, according to Politico.

In February he fought with Howard Dean about the DREAM Act and said it should be available to people who serve in the military or enter the country as children.

Gingrich has also proposed unusual ideas such as having credit card companies create guest worker ID cards that track workers' legal status by swiping their card, according to Politico.

Gingrich has also asked for employers to use E-Verify, an Internet-based system that allows businesses to determine if employees are eligible to work in the U.S.

Gingrich wants a Citizen Board to decide which immigrants stay and go. He has also advocated for the use of the National Guard at the Mexico border and the deportation of illegal immigrants with multiple arrests, according On The Issues.

Ron Paul

Paul has said that we should pay attention to U.S. borders and not international ones, and churches, not states, should provide services for immigrants.

He does not want to send millions of illegal immigrants home, according to On The Issues. Paul is taking a tough stance, though, in his desire to amend the constitution to remove aliens’ birthright citizenship. Paul has also said that he thinks a border fence is not important.

On Paul’s website he has a six point plan to stop illegal immigration which is: physically secure borders and coastlines, enforce visa rules, no amnesty, no welfare, end birthright citizenship and pass true immigration reform.

Reach associate news editor Hannah Madans here.