Under Utah law, the governor has sole authority to call a special session of the Legislature, with the one exception of a veto-override session.
Herbert and the Legislature are at odds largely because the governor wants to ensure that special election candidates have the opportunity to qualify for the ballot by collecting signatures. He also wants 3rd Congressional District voters not just party delegates to choose Chaffetz's replacement.
Lawmakers talk instead about allowing some 1,000 state delegates in the district to pick their party nominee, or even appoint Chaffetz's successor.
Herbert said he opposes such an exclusive process. "By the Constitution, this is an election. This is not an appointment. Therefore, the Utah voters must have access to the ballot if it's going to be an election."
While legislators say they should be called into special session to write specific rules for a special election, Herbert said, "We have statutes in place that tell us what we should be doing," and past legislators gave governors flexibility on how to do that.
Utah law says simply that to fill a vacancy for a U.S. House member, "The governor shall issue a proclamation calling an election to fill the vacancy."
Herbert said while current lawmakers may now want to create more specific rules, past legislatures wrote laws recognizing "there should be latitude given to the executive branch" by not including specifics and he intends to use that flexibility.
"I want to correct the narrative … that the Legislature has somehow not had a say," he said. "They have. They've had a number of years in fact to address it and modify."
In fact, the Legislature in its session earlier this year debated a measure to set rules for a special election to the U.S. House, but the bill died.
Hughes, the House speaker, issued a statement pointing to the U.S. Constitution and federal law in insisting that the process for elections is a responsibility of the legislative branch.
"This is a separation of powers issue. The House and Senate majority caucuses are unanimous in their support for a special session," said Hughes, adding that Democrats also have spoken up in favor of the Legislature's involvement.
The statement said Hughes "remains committed to defending the legislative process and calls on Governor Herbert to convene a special session of the Legislature to vote a clearly defined process into law."
Senate President Wayne Niederhauser also issued a statement pointing to federal law on elections and supporting a special session.
"The path forward with the least amount of legal risk would be for the governor to call a special session to allow lawmakers to add appropriate election language to the state code," he said.
Herbert said that special sessions usually are called only when unanimity on an issue exists, and "we don't even have consensus with the legislators on what to, in fact, pass in a special session."
Herbert said it could turn into a free-for-all, and "that's not what special sessions are for."
The Republican governor said his office has come up with several scenarios on how to hold a special election relatively quickly much faster than the 328 days that Hughes says existing statutes would require if followed precisely.
Herbert said one alternative suggested by legislators who want parties to choose nominees could take as little as two months. He said others, including allowing signature gathering, could take four months.
Chaffetz told reporters Thursday he worked with the governor to allow the special election to possibly coincide with this year's municipal elections, reducing the cost of a special election.
"I understand the importance of doing it quickly" so Utah's 3rd District won't lack congressional representation for long, Herbert said. "But I also believe we want to get it right, which trumps doing it quick."
Herbert said procedures he is studying would likely require both a primary and general election, but not necessarily.
"It depends on what happens. For example, say nobody got signatures. That would eliminate that part." And party delegates may select their nominee and avoid a primary if one candidate received more than 60 percent of the delegate vote.
"I want to do the right thing for the right reasons so we have the right outcome," Herbert said.
Utah has replaced a U.S. representative at midterm only once nearly 90 years ago when then-Rep. Elmer O. Leatherwood, R-Utah, died in office Dec. 24, 1929, at age 57.
His seat remained vacant for more than 10 months. The state at that time went through the normal caucus-convention system, with parties picking nominees for a special election to complete Leatherwood's term and also the next full term. Voters cast ballots for both on Election Day 1930.
Republican Frederick C. Loofbourow was elected both to serve the last couple of months of Leatherwood's term and his own two-year term, taking office immediately after the Nov. 4, 1930, election. Newspaper archives show he won the GOP nomination by beating two other candidates at the party convention.