CHEYENNE, Wyo. (AP) — Voter registration trends suggest strong support for Republican-dominated governance ahead of Tuesday's election in Wyoming, where Republicans have held every federal and statewide office for almost eight years and Democrats increasingly struggle to compete.

Mary Throne, a former Wyoming House minority leader from Cheyenne, is the Democrats' most experienced candidate for governor since Democrat Dave Freudenthal won a second term 12 years ago. Jackson businessman Gary Trauner is Democrats' best-funded — and possibly best-organized — candidate for the U.S. Senate in Wyoming in at least 20 years.

Throne faces Republican State Treasurer Mark Gordon in the race to succeed Republican Gov. Matt Mead, who is term-limited. Trauner seeks to deny Republican Sen. John Barrasso a second full term.

Voter registration figures alone show tough odds for Throne and Trauner. Republicans now outnumber Democrats in Wyoming by well over 4 to 1. Democratic registration is down to just 16 percent compared to 26 percent a decade ago.

Meanwhile, widespread support for low-tax, reduced-regulation and fossil-fuel-friendly policies under President Donald Trump and the Republican-dominated state government leaves Wyoming's Democrats with little room to make a case for significant change.

By many measures, times have been tough in Wyoming since 2014, when oil drilling all but ground to a halt amid weak markets for natural gas and thermal coal.

Wyoming needs to re-examine its tax structure and diversify its economy to better weather the boom-and-bust cycles of the fossil-fuel industries that supply 70 percent of state revenue, Throne argued during her campaign.

"Wyoming is facing some incredible challenges. If we keep doing things the same old way, we will not be able to survive those challenges," Throne said at a debate.

She opposes implementing a state income tax — Wyoming is one of just seven states without one — but has hinted that other new taxes or revenue sources might be necessary.

Gordon, who was a businessman and rancher before being appointed treasurer after the death of Joe Meyer 2012, advocates tighter state spending instead. Businesses looking to move to Wyoming want assurances the state won't change its tax structure, Gordon said at the debate.

"There really is no need for a personal income tax and I'm against the taxes already. I think one of the most important things is how we get a fiscal situation that is sustainable and stable over time," Gordon said.

Trauner has faced the task of criticizing Barrasso's support for Trump, who boosted Wyoming's biggest-in-the-nation coal industry by lifting a federal coal-leasing moratorium and rolling back plans to regulate greenhouse gas emissions.

"Things are really looking up in Wyoming. We have a strong, healthy economy and a growing economy," Barrasso said in a debate.

Wyoming's unemployment rate is about 4 percent. Yet many continue to struggle with stagnant wages, Trauner countered.

Recent income tax cuts signed by Trump will do more harm than good over the long run, said Trauner.

"We're mortgaging our future," Trauner said.

Wyoming U.S. Rep. Liz Cheney faces her first general-election test in Greg Hunter, a little-known environmental consultant from Laramie.

Hunter promises to advocate for universal health coverage and campaign finance reform. Cheney's record as a freshman congresswoman includes support and sponsorship of several bills that seek to help the fossil-fuel industries.

Polls will be open from 7 a.m. to 7 p.m. Tuesday.