State Senate Republican leaders Friday warned Gov. Jared Polis that a proposed special session to deal with an expected TABOR refund slated for next spring would likely be unsuccessful.

In a letter to the governor, Senate Minority Leader Chris Holbert of Parker and Assistant Minority Leader John Cooke of Greeley noted that Polis had been willing to discuss a reduction in the state income tax from 4.63% to 4.59%.

That proposal is contained in one of three bills fellow Republican Sens. Jack Tate of Centennial and Owen Hill of Colorado Springs have been floating with Democrats in the General Assembly.

In addition to the reduction in income tax, which Polis supported in his first State of the State address last January, discussions have touched on modifications to spending limits under the Taxpayer’s Bill of Rights, better known as TABOR.

Those modifications, as detailed in draft bills, would allow the state to retain as much as $575 million in surplus revenue that would otherwise be refunded to taxpayers next spring through one of several refund mechanisms. It would be the second largest refund in state history, after the 1999-2000 year, when $746.2 million was refunded to taxpayers. 

“Your measured approach to encourage such discussions without threatening a special session has allowed legislators to consider a variety of alternatives ranging from statutory changes that could be made by the General Assembly to additional questions that could be referred to voters in November,” Holbert and Cooke wrote.

The two warned that changes to TABOR spending limits would not be viewed favorably by the majority of the Senate Republican caucus.

And a special session is unlikely to produce a bill that will gain the 18 votes in the state Senate, they explained. While a reduction in the state income tax is growing in favor within the Senate minority, Senate Democrats are increasingly opposed to it, the letter indicated.

At the same time, as support for modification in TABOR spending limits grows among Senate Democrats, the opposite is true for Senate Republicans, they wrote.

While they are prohibited by law from adopting a position on behalf of the caucus, “We are confident that we understand the various positions held by the 16 members of the Senate minority caucus,” the letter stated.

That comes in contrast to a letter sent by House Republicans earlier this week, signed by all 24 members and authored by the caucus’s leaders, which stated all members of the caucus oppose a special session.

“The bottom line … is that no proposal seems to have garnered the 18-vote threshold,” the letter concluded, asking Polis not to call a special session and instead wait for the voters’ decision in November on Proposition CC.

That measure will ask taxpayers to allow the state to keep revenues that exceed TABOR spending limits, beginning in the 2020-21 year. 

A spokesman for the governor referred to a statement issued Wednesday in response to House Republicans’ call to reject a special session. 

“The governor was elected to solve problems and bring people together, and that’s what he is doing,” Polis said in the statement. “The governor has been engaged in listening to Democrats and Republicans to better understand their fiscal priorities, and there have been many fruitful conversations.”

According to the Secretary of State’s Office, no statutory deadline exists for referred measures from the General Assembly. However, any measures referred to the ballot would have to be in by the date of ballot certification for 2019, which is Sept. 9.