SPRINGFIELD (Illinois News Network) — Illinois state Sen. Sam Mccann (R-Plainview) announced Thursday that he plans run as a third-party candidate for governor – a move that likely would siphon votes from incumbent Gov. Bruce Rauner.

The first-term governor is widely viewed as an underdog in the race for the state’s highest office against billionaire J.B. Pritzker. McCann’s campaign with the Conservative Party stands to draw votes away from Rauner, who has alienated many conservative voters. Rauner narrowly defeated state Rep. Jeanne Ives in the Republican primary last month.

“When I announced I was not going to run for Senate, I said the Republican Party under Rauner was unrecognizable to me,” McCann said in a statement. “Rauner has smeared the reputations of proven conservatives and abandoned the principles that millions of Illinois’ working families hold dear: economic liberty, traditional values, and law and order.”

McCann, first elected in 2010, is known for bucking his party and siding with Democrats. His state Senate campaign has accepted more than $100,000 from Union groups in recent months. International Union of Operating Engineers Local 150 gave the campaign $50,000 this week.

Rauner touts that he has never accepted union donations.

Local 150 has given money to Republicans in the past, but more commonly supports Democrats.

In a campaign video released Thursday morning, McCann blames Rauner and Chicago Democrats for high taxes and corruption in the state.

“As conservatives, we believe that you can’t spend money that you don’t have,” McCann said. “As your governor, I will work with the General Assembly to appeal Rauner’s tax increase.”

Rauner vetoed the $5 billion tax increase. A group of Republicans joined Democrats in 2017 to override Rauner’s veto. The move raised the state’s personal income tax rate to 4.95 percent from 3.75 percent and the corporate rate to 7 percent from 5.25 percent.

Republicans, including Rauner’s campaign, are bashing McCann for using union donations to try and spoil the matchup between Pritzker and the incumbent Republican.

Rauner’s campaign dismissed McCann’s bid as self serving.

“Sam McCann is the worst kind of political opportunist who is only running for governor to line his own pockets,” Rauner campaign spokesman Will Allison said in a statement. “McCann’s unethical record speaks for itself: he failed to pay his taxes, racked up massive debts, lied about serving in the Marine Corps, and used his campaign account as a personal piggy bank, even buying himself an SUV. Public service should not be for personal gain and Sam McCann’s new ‘campaign’ is just a thinly veiled attempt to profit off of politics.”

Rauner is in Germany on a business-courting trip.

Pritzker welcomed McCann’s candidacy.

“I welcome another voice to the race for governor at this critical time for our state,” Pritzker said in a statement. “Bruce Rauner is a failed governor who has done untold damage to communities throughout Illinois, and people from across the political spectrum are ready for change.”

Pritzker is running on implementing a progressive income tax that could increase taxes on many Illinoisans. He’s not saying what rates he seeks to impose on which income brackets.

McCann also resigned from the Illinois Senate Republican Caucus.

McCann has sided with Democrats and public unions in attempts to grow the size of government several times, most notably in a 2016 attempt to override Rauner’s veto of a union-supported arbitration bill that would have placed labor negotiations between the state and the American Federation of State, County and Municipal Employees Council 31, it’s largest public union, into the hands of an arbitrator. The veto was narrowly upheld in the House.

Rauner had fought the bill, saying it would have removed his ability to negotiate a better deal for taxpayers.

Senate Minority Leader Bill Brady, R-Bloomington, disputed McCann’s conservative credentials.

“The Illinois Republican Party didn’t leave Sam McCann,” Brady said in a Tweet on Thursday. “He left the Republican Party with his lockstep votes to support Mike Madigan’s agenda of unbalanced budgets and putting the interests of public sector unions ahead of Illinois taxpayers.”

The Democratic Governors Association said Thursday in a release that voters who supported Rauner’s conservative primary challenger, Rep. Jeanne Ives, now have another conservative choice.

Ives declined to respond to the comment.

The election is Nov. 6.