Donald Trump and his GOP colleagues have exposed the depth of the divide in attitudes over the role of American Muslims in US society. The results of a recent Zogby poll establish that the divide is more existential than merely rhetorical, and is more demographic than simply partisan. It has become a matter less of competing political philosophies and more a question of the attitudes of the groups that now make up the mainstream of each party.

To be clear, fear of Muslims is not just a function of what this or that candidate says, because what the candidates are saying is a reflection of what the significant parts of the constituent base each party believes. And the two major parties are increasingly defined by the distinct demographic groupings of Americans that make up their core supporters.

When Republican candidates, for example, maintain that Muslims should not be trusted, that Muslim immigrants be banned, or that Muslims should be profiled, or when candidates pledge to block President Obama's commitment to bring Syrian refugees to the US, or claim that Obama is a closet Muslim—they are echoing the views of a strong majority of Republican primary voters. Our polling bears this out and it is a reality that must be understood and addressed.

The poll of slightly over one thousand likely voters was conducted by Zogby Analytics in the days after Trump made his comments calling for a ban on Muslim immigrants into the US. It found that Trump continues to hold a substantial lead over the rest of the GOP field with the support of 38% of Republican likely voters and Hillary Clinton at 56% maintains a commanding lead over her Democratic rivals.

We also asked all respondents a series of questions about their attitudes towards Arab Americans and American Muslims. The results were deeply disturbing, with the overall views of Democrats and Republicans being near mirror reflections of one another. For example, while Democrats had a 51% favorable view of Arab Americans compared with 23% who held unfavorable views and had a 44%/28% net favorable view of American Muslims, Republican attitudes of Arab Americans were 34% favorable/44% unfavorable and a 26%/53% net unfavorable rating for American Muslims.

Similar divergent views were found with regard to whether or not voters felt confident that an Arab American or an American Muslim could faithfully carry out their responsibilities in a government position. In each case, Democrats agreed that they could, while a majority of Republicans felt that Arab or Muslim Americans would be unduly influenced by their ethnicity or their religious faith.

And the same divide could be found in response to questions regarding whether Arab Americans and American Muslims should be profiled or whether Syrian refugees should be admitted to the US, with six in ten GOP voters saying that Arab Americans and American Muslims should be profiled and the same percentage rejecting the president's goal of accepting 10,000 vetted Syrian refugees a year.

The most striking gap occurred in response to the question about the president's religion with only one in ten Democrats believing that Obama might be Muslim and almost seven in ten Republicans asserting that he was either a Muslim (49%) or had no faith at all (19%).

In each instance, this partisan split masks a deep demographic divide, with older, white, less educated voters, especially those who are self-defined as "born again Christians" making up the largest proportion of Republicans, and African American, Hispanic, younger, and more educated voters making up the Democratic side.

The poll also defined two important behavioral characteristics that, in addition to demographics, helped to shape attitudes of voters on these issues: voters' sources of news and whether or not they know any Arab and Muslims. As expected, those who rely on Fox News held largely negative views on all these issues, but the same was also true of CNN viewers. On the other hand, the 30% of voters who rely on Internet or other news sources had significantly more favorable views on all the questions covered in the poll.

Similarly, the 30% of all voters who knew Arabs and Muslims had substantially more favorable views of both communities and were more opposed to profiling them than the population, at large. And, once again, in each instance, we observed the same demographic divide in the make-up of each group.

As significant as this Democratic/Republican divide might be, it becomes even more dramatic when we compare the attitudes of the sub-set within each camp who are supporting their party's leading candidates. While 53% of Trump supporters have negative views of Arab Americans and 68% have negative views of American Muslims, 69% of Clinton supporters have favorable views of Arab Americans and 63% view American Muslims favorably. And while only 6% of Trump supporters believe the President Obama is a Christian (60% claiming he is a Muslim), only a handful of Clinton supporters say the president is Muslim while 74% believe Obama is Christian.

The Zogby poll identifies the magnitude and contours of the problem. It is, to be sure, grave, for American Muslims and for my community of Arab Americans, as well. Not only that, it is dilemma for the Republican Party and for America—with no easy answers in sight.

A short while ago, I had a leading Republican strategist on my weekly TV show. I asked why the GOP establishment wasn't more decisive in confronting Trump. His responses were telling. On the one hand, because Trump, Carson, and Ted Cruz are running against the establishment, attacks by that very group would only strengthen their appeal. And with these three candidates garnering almost 60% of the GOP vote, the establishment is concerned about the risks involved in alienating such a substantial base of their party. While that may be their concern, mine has to be for my community and my country.

In recent weeks, some Republican leaders have denounced Trump's more outrageous positions (though some were careful not to denounce Trump, himself). Senator Lindsay Graham, however, distinguished himself with a full-throated rejection of Trump and his views. Because we are caught up in a horrific situation that we must be relentless in confronting—for our present security and for our future stability—we can only hope that more GOP leaders will follow Graham's example.