WASHINGTON, D.C. -- Immigration has become a significant issue in the 2016 presidential campaign, in large part because of Republican candidate Donald Trump's continuing emphasis on high-profile proposals to restrict who comes into the country and to determine what happens to immigrants here illegally now. There is little doubt that immigration will be a major challenge for the next president, particularly given that the U.S. is consistently among the most desired destinations for potential migrants. This Gallup review looks at key aspects of American public opinion on immigration, including in particular a focus on what the average American wants their next president to do.

Immigration Is a Medium-Rated Priority for Americans

In early October, 7% of Americans rated immigration as the "most important problem" facing the country, roughly in line with where it has been for the last year. However, these top-of-mind mentions of immigration as the top problem have varied significantly over the years, reaching as high as 19% in April 2006 and, more recently, 17% in July 2014. Prior to 2000, immigration generally was infrequently mentioned as the nation's top problem.

The October most important problem update shows immigration tied with elections and national security as the fourth-most-frequently mentioned problems. Immigration has appeared as one of the top five problems in the United States in 52 of the last 190 months.

Fourteen percent of American respondents told Gallup in May that immigration was the single issue or challenge they were most interested in having the next president address when he or she takes office. Immigration was second only to the economy as an answer to the open-ended question.

However, in the same May survey, when asked to rate the importance of specific issues to their vote, 69% of Americans rated immigration "extremely" or "very" important, putting it in the middle of the list of 17 issues tested.

The contrast between the relatively high ranking of immigration for the open-ended question and the lower ranking in a list of issues suggests that immigration is of high importance to a specific segment of the population -- whose mentions drive up the open-ended ranking -- but indicates it is of lower importance to the population as a whole.

Americans' Basic Feelings About Immigration

Americans clearly say that immigration in a general sense -- that is, not focused just on immigrants who enter the U.S. illegally -- is good, rather than bad, for the country. Since 2001, the percentage of Americans identifying immigration as a good thing for the United States has averaged 63% and has never dipped below 50%. Most recently, in Gallup's Minority Rights and Relations poll conducted June 7-July 1, 2016, over seven in 10 Americans identified immigration as good for the country.

Despite this general perception that immigration is good for the country, the percentage of Americans who say they are satisfied with the current level of immigration into this country is well below a majority. Gallup's January Mood of the Nation survey showed that three in 10 Americans are satisfied with the level of immigration into the country today, ranking it near the bottom of a list of 22 issues tested. A follow-up question shows that the majority of those who are dissatisfied with immigration want fewer, rather than more, people entering the country.

Americans are more likely to say that immigration should be decreased or kept at the present level than to say it should be increased. When Gallup last asked, "In your view, should immigration be kept at its present level, increased or decreased?" 21% of Americans said it should be increased, 38% said it should be decreased and 38% said it should remain at its current level.

The percentage of Americans saying immigration should be kept at its present level or decreased has fluctuated since 2001, while the percentage saying it should be increased has slowly climbed. The percentage of those saying immigration should be decreased peaked in the mid-1990s at 65%, around the same time immigration appeared as one of the most important problems facing this country.

These results suggest that while Americans -- most of whom, of course, descended from immigrants themselves -- recognize that immigration, in a broad sense, is good for the country, many have significant concerns about the current level of immigration. Gallup research also shows that Americans' views on the level of immigration are more consistent with views in other countries -- such as Canada and Australia -- that are also top destinations for migrants.

Americans' Views on Clinton Versus Trump on Immigration

Both presidential candidates have laid out plans to address the flow of immigrants illegally coming into the country today, as well as the millions of immigrants already in the country illegally.

When asked to make choices, Americans show themselves to be in greater alignment with Clinton than with Trump. A mid-September update shows that Americans give Clinton a 13-percentage-point edge over Trump when asked which candidate would do the better job handling immigration.

Despite his relative perceptual deficit to Clinton on the issue, it is clear that Trump's campaign has been strongly associated with the issue. In August 2015, Gallup asked Americans what words and phrases they had read, seen or heard in recent days about key presidential candidates. For Donald Trump, "immigration" was the most frequently mentioned word. A year later, with the pool of major candidates narrowed down to two, "immigration" was still prominent in Americans' perceptions of what they had read, seen or heard about Trump in the summer months, although the issue was eclipsed by other issues in their minds during and after the conventions and during the debates.

Halting Flow of Illegal Immigrants or Dealing With Immigrants in U.S.

Asked to make a choice between the government focusing more on halting the flow of illegal immigrants into the U.S. or developing a plan to deal with immigrants who are currently in the country illegally, Americans tilt slightly toward dealing with the latter. By contrast, when this question was asked in Gallup polls conducted between 2006 and 2011, at least half of Americans opted for an emphasis on halting the flow of immigrants coming into the country illegally. The current tilt toward dealing with immigrants already in this country illegally has been evident in surveys conducted since 2012.

If you had to choose, what should be the main focus of the U.S. government in dealing with the issue of illegal immigration -- [ROTATED: developing a plan for halting the flow of illegal immigrants into the U.S., (or) developing a plan to deal with immigrants who are currently in the U.S. illegally]? Halting flow of illegal immigrants Deal with immigrants in the U.S. illegally No opinion % % % Jun 7-Jul 1, 2016 45 51 4 Jun 5-8, 2014 41 53 6 Feb 6-9, 2014 46 51 2 Jun 13-Jul 5, 2016 41 55 4 Jun 7-10, 2012 41 55 5 Jun 9-12, 2011 55 43 2 Jun 11-13, 2010 50 45 5 May 1-2, 2010 53 45 3 May 5-7, 2006 52 43 4 Gallup

Research conducted in previous years shows that over three-quarters of Americans say it is "very" or "extremely" important to control the borders to halt the flow of illegal immigrants into the country, and over three-quarters say it is important to develop a plan to deal with illegal immigrants already in this country.

In short, these issues are not necessarily a case of either/or for the American public, but rather a case of dealing with both the borders and immigrants living in the country illegally now.

Stopping Illegal Immigration by Building a Wall

Trump's proposal to build a wall between the U.S. Southern border and Mexico was one of his first pronouncements to gain the attention of the voting public, and it has since become one of his oft-repeated and signature proposals. Americans, however, are clearly not sold on the idea. When Gallup asked Americans in June and July about building a wall, 33% favored the idea, while 66% opposed it, including 41% of Americans who said they strongly opposed it.

Favor or Oppose Building a Wall Along the Entire U.S.-Mexico Border Favor 33% Oppose 66% Gallup, June 7-July 1, 2016

As noted previously, a majority of Americans clearly support the general idea of stopping immigrants from coming into the country illegally, and research from several years ago showed 83% support for tightening security at U.S. borders. The public at this point, however, simply doesn't believe that a wall along the entire border is the way to accomplish that goal.

Pathway to Citizenship Versus Deporting Back to Home Country

Plans for dealing with immigrants already in this country illegally include Hillary Clinton's emphasis on allowing them to stay in the U.S. if they meet certain requirements and Donald Trump's emphasis on deporting them. While Clinton calls for "a pathway to full and equal citizenship," Trump emphasizes a process that involves sending some of them home, saying, "Anyone who has entered the United States illegally is subject to deportation."

The American public clearly comes down on the side of some type of pathway to citizenship. Some 84% favor allowing immigrants "living in the U.S. illegally the chance to become U.S. citizens if they meet certain requirements over a period of time."

Favor or Oppose Allowing Immigrants Living in the U.S. Illegally the Chance to Become U.S. Citizens if They Meet Certain Requirements Over Time Favor 84% Oppose 15% Gallup, June 7-July 1, 2016

A separate Gallup trend question offers three alternative solutions for dealing with illegal immigrants living in the U.S. When given specific options, the results show that 65% of Americans favor allowing these individuals to remain in the U.S. and become citizens if they meet certain requirements over time, 19% favor allowing them to remain and work for a limited time, and 14% say that they should all be deported to their home countries.

Stopping Muslims From Entering the Country

Another Donald Trump proposal -- one that gained him a great deal of publicity when first promulgated -- was the idea of banning Muslims who are not U.S. citizens from entering the United States. Thirty-one percent of Americans agree with this proposal, while 52% disagree and 17% have no opinion.

Agree or Disagree: Ban Muslims Who Are Not U.S. Citizens From Entering the Country Agree 31% Disagree 52% No opinion 17% Gallup, March 9-13, 2016

Bottom Line

The next president of the U.S. will face the significant challenge of dealing with immigration issues -- handling the flow of immigrants who desire to come into the country legally, the flow of those who already come into the country illegally every day and the millions of those who are already in the country illegally. While the public does not give immigration top priority as an issue, it's clearly important, and the rhetoric surrounding the issue in this presidential campaign signals continuing controversy in the months ahead. Of course, as is true about much else in the public policy arena, these issues are not new; President Jimmy Carter faced questions about amnesty for immigrants in the country illegally almost 40 years ago.

Americans recognize that immigration is good for the country but have reservations about the number of immigrants coming into the country. Americans favor controls on who comes into the country legally, but do not favor restricting whole groups of people based just on their religion. Americans favor efforts to halt illegal immigration in general, but they do not favor building a wall along the nation's Southern border. The public also supports the development of some method for dealing with immigrants already in the country illegally, including developing a pathway to citizenship, but Americans do not favor mass deportations.

One thing is for sure: Americans will be paying close attention to the candidates' stances and rhetoric on immigration in the runup to the November election. A majority (58%) of Americans in 2015 said they considered stances on immigration among other issues when selecting a candidate for political office, and 20% said the candidate must share their views.