BOISE, Idaho (AP) — Idaho last year was the nation’s fastest-growing state, with close to 37,000 new residents boosting its population to nearly 1.8 million.

In the past decade, according to the U.S. Census Bureau, the deeply conservative state has seen a population jump of more than 200,000. Studies indicate many have come from liberal-leaning California, Oregon and Washington.

But are those new residents bringing blue-state politics? Or are they Republicans fleeing the coast for conservative Idaho?

An answer could emerge Tuesday when Idaho holds its presidential primaries. Democrats are using a primary for the first time after picking Sen. Bernie Sanders over Hillary Clinton at a caucus in 2016.

President Barack Obama handily won the Democratic contest in Idaho over Clinton in 2008.

President Donald Trump is expected to have little difficulty winning the Republican primary or the state in the November general election. The last time Idaho voted for a Democratic presidential candidate was Lyndon Johnson in 1964.

Still, officials say switching to a Democratic primary this year could significantly increase the number of participants, and play a role in the outcome.

Former vice president Joseph Biden drew more than 100 donors at an Idaho event in August. Sen. Elizabeth Warren had scheduled a visit this weekend but ended her campaign Thursday.

“We hope that Idaho continues to grow in diversity and political affiliation, and that will strengthen our party and candidates,” said Lindsey Johnson, spokeswoman for the Idaho Democratic Party.

Jaclyn Kettler, a Boise State University political scientist, said it appears Democrats, in general, are moving to urban areas and Republicans to more rural areas, continuing the urban-rural divide between Democrats and Republicans prevalent in states in the U.S. West.

“We’ve definitely seen some areas like Boise becoming bluer in the last few years,” she said. “More conservative voters are moving into Canyon County and northern Idaho.”