Every once in a while, you can find someone wanting a position so badly — or so badly wanting to deny a position to someone else — that the person will blow past the boundaries that separate acceptable and unacceptable in the caustic world of political argument.

Of course, what’s acceptable and unacceptable is completely in the minds of the voters. They split on partisan lines, of course, eager to believe the best about their own and the worst about their opposites. But some kinds of attacks hit a different mark — scattering supporters of the attacker and rallying voters to the side of the target.

Like this business about the mental health of state Sen. Dan Patrick, R-Houston, which became the central topic of debate just ahead of early voting in the GOP runoff for lieutenant governor. It echoes the descent of decency in the 1990 Democratic runoff for governor, a contest that pitted Attorney General Jim Mattox against state Treasurer Ann Richards.

Mattox accused Richards — live, on national TV, at one point — of abusing illegal drugs in the past. Richards, a clean-and-sober alcoholic who had been open about her recovery, refused to answer a hailstorm of questions from reporters that went on for weeks other than to say she had not used any mind-altering substances for the previous 10 years. No hard evidence emerged, but the fact that the accusations were coming right out of the mouth of a sitting attorney general and in a high-profile race made it the main issue of the contest.

Richards won that primary runoff. The best evidence of how it worked for Mattox was that Republican Clayton Williams Jr. of Midland didn’t take up that particular attack — at least directly — in his race against Richards. Voters had heard it in the primary and had taken a pass on it.

A candidate has to travel a pretty fair distance to go over the line in a state where just about any kind of human experience or condition seems to be fodder for political campaigns and civic conversations.

Texans witnessed a straight dose of religion in politics when conservatives lined up behind Republican challengers to a second term for House Speaker Joe Straus, R-San Antonio, in late 2010 and early 2011. Straus, the first Jewish speaker of the Texas House, won that one, but the email and online traffic against him was a wonder of old-school negative campaigning.

Pictures of candidates’ cars parked overnight at the homes of men and women to whom they are not married are commonplace in politics, and in Texas legislative races. Drunken driving records — sometimes decades old — appear from time to time. Republican Rick Perry ran an ad against Democrat Tony Sanchez Jr. in their 2002 gubernatorial race that contended a savings and loan owned by Sanchez had laundered money for Mexican drug dealers who killed an American agent for the Drug Enforcement Administration. Sanchez cried foul, but Perry won.

Trotting out mental health issues that are both old and somewhat disconnected from the set of tools required to serve as lieutenant governor tests the limit. Even people who don’t like Patrick and/or his politics have been cringing and wincing. They might not be taking his side, but they do not seem to be racing to defend the attacks.

Even the intended beneficiary of all of this is running from it. Lt. Gov. David Dewhurst, who finished well behind Patrick in the March primaries, has been trying to catch up in the runoff. Despite some evidence that people associated with his campaign were involved, he has said he didn’t have anything to do with bringing the information about Patrick into public view.

Land Commissioner Jerry Patterson, one of two candidates who failed to make the runoff for lieutenant governor, is the primary source. He found a trove of legal papers — depositions and the like — from a lawsuit Patrick filed against a Houston reporter after the two fought in a restaurant parking lot. Those contain details about two times Patrick was hospitalized for depression. Patrick, in response, said he was treated at the time and that he has had no further treatment or medication since 1987. And he blamed Dewhurst for bringing his treatment into the campaign, shaming him and accusing the incumbent of taking a desperate strike at Patrick’s reputation.

Dewhurst blew the whistle when people were talking more about dirty politics than about Patrick’s mental acuity. Patterson has not backed down. “Dewhurst has asked me to cease distribution of this information,” he wrote in an email to reporters. “He also asked me not to run against him for LtGov. I didn't really give a damn what David wanted then, and I don't give a damn now. The voters of Texas need to know. They're going to find out between now and May 27th, or they're going to find out between May 27th and November.”

Patterson has maintained throughout the race that he does not believe Patrick is truthful, and that his voluminous document dump is not about the senator’s mental health but about “the pattern of lying and obfuscation about this long-ago incident.”

But that doesn’t appear to be how this is playing out. While his foes seek some kind of referendum on Patrick, they might get something else entirely. The votes get counted a week from now, a verdict of sorts on how far attacks can go in Texas politics.