Almost half of Republican voters favor deporting all immigrants here illegally and barring Syrian refugees from entering the United States — a fact that helps explain Donald Trump's resilient campaign for the party's presidential nomination.

Trump first shot to the top of the GOP field by appealing to economically anxious voters who blame illegal immigration for pushing down their wages, reducing their job opportunities and soaking up taxpayer dollars. After this month's terrorist attacks in Paris, which could have made his lack of foreign policy experience a liability with voters, Trump has drawn large crowds and loud applause by calling for the United States to reject refugees from Syria.

Data from the latest Washington Post-ABC News national poll suggest those two issues — immigrants and refugees — differentiate Trump supporters from other Republicans. The numbers also show how linked those issues are for Republican voters this year and how they entwine with voters' preference for an outsider candidate who will bring change to Washington. (For polling wonks, see a note below on sample size and statistical significance).

Nearly half of GOP-leaning respondents in the poll — 47 percent — both support the deportation of undocumented immigrants and oppose accepting refugees from Syria and other Mideast conflicts. If a GOP-leaning voter supports deportation, there is a 79 percent chance she or he also opposes Syrian refugees, compared with 54 percent if they oppose deportation.

Trump has captured the support of 51 percent of those overlapping voters, compared with 16 percent among all other Republican voters. Put another way, pro-deportation/anti-refugee voters account for almost three-quarters of Trump's support. (He's polling at 32 percent overall in the Post-ABC poll.)

Perhaps as important for Trump, his two leading rivals from the so-called establishment wing of the party fare quite poorly with the anti-immigration/refugee group — which, again, appears to comprise nearly half the GOP electorate. Jeb Bush polls at 6 percent with that group. Marco Rubio polls at 5 percent. Ben Carson polls at 19 percent; if Trump could woo all those Carson voters his way, he'd be within shouting difference of an outright majority in the primary field.

Anti-immigrant/refugee voters cross traditional Republican constituencies — 32 percent identify as "very conservative," but 39 percent say they are moderate or liberal (similar to other Republicans). Just over one-third are white born-again Protestants, identical to the share other Republicans. They differ in their level of education — 48 percent have a high school degree or less, compared with 33 percent of other Republicans.

Establishment Republicans probably shouldn't count on voters from the immigrant/refugee group not showing up on Election Day. Members of the group are at least as likely to be following the election “very closely” as other primary voters (44 percent compared with 36 percent of others), and they’re about as likely to say they are certain to vote.

They also believe their man can win: 52 percent of voters who support deportation of immigrants say Trump has the best chance of getting elected in November 2016. That drops to 24 percent among those who oppose deportation or support allowing refugees from Syria and other countries into the United States.

Trump is also running well ahead of his rivals among voters who say the most important attribute in a presidential candidate is her or his likelihood of bringing needed change to Washington. Some of his opponents, such as Bush, have attempted to cast themselves as agents of change, though of a different sort than Trump. The poll offers some cautions on that strategy, for candidates (such as Bush) who break from Trump on the deportation and refugee issues.

Fifty-two percent of Republican-leaning adults say it’s most important for them to support the candidate who is likeliest to bring needed change to Washington, compared with 28 percent who prioritize honesty, 11 percent experience, 4 percent electability and 2 percent personality and temperament.

Of those who prioritize change, 67 percent support deportation and 74 percent oppose Middle Eastern refugees, both higher than among Republicans who prioritize other attributes (46 and 62 percent, respectively ).

More than half of these change-focused Republicans — 56 percent — both support deportation and oppose refugees.

Other Republicans still have several paths to beat out Trump for the nomination. A rival candidate could consolidate the support of GOP voters who oppose deportation and/or support refugees. Carson or, perhaps, Ted Cruz could find a way to steal Trump's voters from the deport/no refugee group. Looked at another way, the less politically troublesome opposition to refugees might serve as an opportunity for establishment Republicans to connect with these voters without staking out strong opposition to welcoming undocumented immigrants. Lastly, elite concerns about Trump's electability may could spread as primary season rolls around or if Trump wins Iowa, galvanizing opposition around another candidate.

Or any candidate could find another issue to overwhelm Trump among white Republicans without a college degree, the voters most likely to both support deportation and oppose refugees. That issue would have to be more important to those voters than immigration and migration concerns. Which almost certainly means it would need to speak directly to their economic anxiety which helped lift Trump's candidacy in the first place.

The Post-ABC poll was conducted Nov. 16-19 among a random national sample 1,004 adults reached on cellular and land line phones by live interviewers. Full question wording and methodological detail is available here.

Note on sample size and statistical significance: The breakdowns below are based subgroups of the 423 Republicans and GOP-leaning independent adults and 373 registered voters. The sample size for deportation/anti-refugee Republican voters is 163, while the sample size for all other GOP voters is 209, carrying margins of sampling error of nine and eight points, respectively. While sample sizes are small, all reports of differing attitudes between groups below have passed standard tests of statistical significance at the 95 percent confidence level.

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U.S. Republican presidential nominee Donald Trump speaks at a campaign event at Trump Doral golf course in Miami, Florida, U.S. July 27, 2016. REUTERS/Carlo Allegri (Carlo Allegri/Reuters)