State Treasurer Walker Stapleton has twice the support of Attorney General Cynthia Coffman, his next-closest rival, for Colorado’s Republican gubernatorial nomination, but just as many voters are undecided as support either of the two frontrunners, according to a poll released Monday by GOP firm Magellan Strategies.

The survey shows Republican primary voters overwhelmingly approves of the job President Donald Trump is doing and  thinks enforcing federal immigration laws should be the top priority for GOP candidates for governor.

It’s the first publicly available polling for the race since former U.S. Rep. Tom Tancredo, who had led the pack in previous polls, dropped out a little over a month ago. With Tancredo gone, the pollsters said, the field “appears to finally be settled,” but a decisive share – half the voters who say immigration is their top issue and 39 percent of respondents over all – are still undecided, with 16 weeks to go until the June 26 primary.

Stapleton led Coffman 26-13 percent, with former investment banker Doug Robinson scoring 8 percent and entrepreneur Victor Mitchell coming in at 5 percent support, with 9 percent choosing “other.”

Among unaffiliated voters – who will have the chance to participate in Colorado’s primaries this year for the first time – Stapleton held a wider lead, with 33 percent support over Coffman’s 11 percent. Robinson had 7 percent, Mitchell had 4 percent, “other” had 12 percent, and 28 percent were undecided. Unaffiliated voters accounted for 10 percent of Magellan’s sample, the pollsters said, consistent with projections about the group’s participation in the primary.

None of the leading Republican candidates are well known among likely Republican voters. Stapleton and Coffman, both statewide elected officials, score best, with only 22 percent saying they’ve never heard of him and 23 percent saying they’ve never heard of her, but an identical 48 percent say they’ve never heard of Robinson or Mitchell.

For Stapleton, 33 percent of respondents had a favorable impression, compared to 13 percent who viewed him unfavorably. It was barely upside-down for Coffman, with 20 percent viewing her favorably and 21 percent unfavorably. Nine percent viewed Robinson favorably and 11 percent viewed him unfavorably, while the same 11 percent viewed Mitchell favorably and unfavorably.

Fully 82 percent of Republican primary voters approve of the job Trump is doing, while 13 disapprove. The GOP-led Congress fares less well, with only 35 percent approving of the job Republicans are doing in Congress and 49 percent disapproving. That marks an improvement, the pollsters note, since October, before tax reform legislation was passed, and only 14 percent of Republican primary voters gave congressional Republicans a thumbs up, while 78 percent disapproved.

Asked which issue was most important for a GOP gubernatorial candidate to address, 43 percent said enforcing federal immigration laws, 13 percent said investing in roads and transportation, 10 percent said keeping a lid on state spending, 9 percent said improving public education, 9 percent said creating jobs and boosting the economy, 8 percent said reducing health care costs and 5 percent said dealing with problems created by legalized marijuana.

The automated voice poll surveyed 647 likely Republican primary voters Feb. 26 and 27 and has a margin of error of plus-or-minus 3.85 percent, the pollsters said. Results were weighted to reflect turnout demographics of past Republican primary elections in Colorado.