Hey, Texplainer: A lot of Republican incumbents are refusing to debate their opponents ahead of the midterms. Is that unusual?

This year, voters will decide who will hold the most powerful elective offices in Texas. But with just three months before the 2018 midterms, only one debate, between the Republican and Democratic gubernatorial candidates, is on the calendar. In Texas races where recent polls have shown a closer-than-normal match-up — U.S. Senate, attorney general and lieutenant governor — candidates are either still going back and forth on whether a debate will actually happen, or have already refused invitations to do so.

Attorney General Ken Paxton and Lt. Gov. Dan Patrick both have said they won’t debate the Democrats running to unseat them this year, drawing complaints from their opponents Justin Nelson and Mike Collier, respectively, that they were making it harder for voters to make informed decisions.

“Debates are an educational opportunity for all Texans to decide how to vote. This is a really important office,” Nelson told The Texas Tribune.

Paxton and Patrick, meanwhile, don’t see the need.

"It’s no secret Lt. Governor Patrick relishes debates, but since his opponent shows no sign of grasping even the most basic rudiments of state government, our campaign has no plans to debate him," Patrick strategist Allen Blakemore said in a statement to The Texas Tribune in July.

Paxton “will communicate directly with the voters,” his spokesman, Matt Welch, previously wrote, denying Nelson’s invitation for a debate. "Now is not the time to turn over the attorney general’s office to an unknown liberal democratic plaintiff trial lawyer who makes a living off destroying small businesses through abusive litigation,” Welch added.

So are the candidates who are dodging debates breaking with tradition? Or is this par for the course in Texas politics? Recent history suggests that it’s usually a toss-up whether statewide candidates debate (for this comparison we are only looking at races for U.S. Senate, governor, lieutenant governor and attorney general):

So what factors into whether candidates choose to debate?

In many cases, it depends on how competitive the race is. Many incumbents — especially well-funded ones with a political edge on their opponents — see no benefit to being part of a debate.

“In 2010 the Republican party had an absolute chokehold on Texas politics. And they all knew it,” said James Riddlesperger, a political science professor at Texas Christian University. “All you do when you debate someone is raise their profile and if they’re behind you by double-digits then there’s absolutely no reason to debate them at all.”

Four years later, however, both major party candidates for the top Texas posts agreed to debate. So what changed?

Historically speaking, debates between the leading general election gubernatorial candidates are common. The exception is Perry, who in 2010 said that he would not debate White until White released 15-year-old tax records from when he served as deputy U.S. secretary of energy.

Paxton and Patrick, however, likely had different reasons for wanting to debate their opponents that year. Given the timing and context, it would have behooved both men to accept debates because they were both still introducing themselves to the whole state, said Sherri Greenberg, a clinical professor at the University of Texas LBJ School of Public Affairs.

This fall, however, is different. Both Republicans have four years of experience under their belts and have significantly outraised both their challengers. So it’s not surprising they turned down their opponents’ invites, said Jeff Blaylock, the publisher of Texas Election Source.

“If you’re a candidate and campaign strategist you have to ask yourself, ‘what is the upside to giving my opponent a wide-open format to challenge me in an unscripted, uncontrolled environment?,’” Blaylock said “There’s no real downside to me, as a candidate, going to friendlier places and rallies and sticking to the script and having only people that I want say nice things about me.”

It’s more common for trailing candidates, often Democrats, to push for and accept debate invitations because they want exposure and a chance to get their platforms and names out to voters.

But for voters hoping to see at least one top-of-the-ticket debate this cycle, all hope isn’t lost.

On Monday, Democrat Lupe Valdez agreed to debate Abbott on Sept. 28 in Austin. A Spanish language media partner will broadcast, moderate and translate the debate, according to a news release sent by Valdez’s campaign.

In the U.S. Senate race, the back and forth over debates goes back to April. Beto O'Rourke, the Democratic nominee in Texas' U.S. Senate race, accepted Cruz's proposal to debate five times over the next three months, but suggested that one of the debates be held in his hometown, El Paso. Cruz's campaign in response said that it would be willing to comply with O’Rourke’s request but nothing has been scheduled yet.

The bottom line: 2014 was the last year that all four top Texas posts (U.S. Senate, governor, attorney general and lieutenant governor) were on the ballot for re-election and both major party candidates participated in at least one political debate that year. The last time there were no top-of-the-ticket general election debates was 2010.

Disclosure: Allen Blakemore, Sherri Greenberg, Texas Christian University and the University of Texas at Austin have been financial supporters of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.