Where a 2016 presidential candidate stands on immigration is extremely important to one in five registered U.S. voters, according to a new Gallup poll released Wednesday.

Twenty percent of respondents said they will only vote for a candidate who shares their views on immigration. An additional 60 percent said a candidate's immigration policies will be one of many important factors taken into account when deciding whom to vote for.

Aside from President Obama's executive actions that provided amnesty to some 4 million immigrants currently in the country illegally, the federal government has been unable to pass a comprehensive reform measure, according to the Washington Examiner.

The issue, in particular illegal immigration, has emerged as one of the most widely discussed and controversial topics of the 2016 election cycle, largely thanks to Republican front-runner Donald Trump. The billionaire real estate mogul has made it a centerpiece of his campaign, promising to deport all illegal immigrants, end birthright citizenship and build a wall along the U.S.-Mexico border, as HNGN previously reported.

The rest of the Republican field hold fairly diverse opinions when it comes to illegal immigration, while practically every major Democratic candidate has publicly backed establishing a pathway to citizenship.

Gallup found that Republican voters were nearly 10 percent more likely than Democrats or independents to only vote for a candidate who shares their views on immigration. Hispanic voters were also much more likely to take the issue into account before backing a candidate.

"Republicans' greater likelihood of saying they must agree with a candidate on immigration in order to support him or her suggests the issue should be a bigger factor in the Republican primaries than in the Democratic primaries. Republican candidates generally place a high priority on border security and do not favor a path to citizenship for undocumented immigrants residing in the U.S. But some, like Trump, go further, offering a number of additional policies to limit immigration, such as deporting all undocumented immigrants and not granting automatic citizenship to children born in the U.S. whose parents are here illegally," wrote Gallup's Jeffrey Jones.

"But in the general election campaign, immigration could work to the detriment of the eventual GOP nominee given immigrants' and Hispanics' above-average desire for agreement with their chosen candidate on the immigration issue, coupled with their generally pro-immigration views."

Only 8 percent of Americans say immigration is the most important problem currently facing the country.

The telephone poll was conducted June 15 to July 10 among a random sample of 1,987 voters aged 18 and older and has a margin of error of plus or minus 4 percentage points.