who is the worst world champion of all time

Max 

Like i said.  You dont even know what you are talking about.

was Alex drunk?

And no we have a 2nd grader asking if someone was drunk.  Kid, youre trying way to hard to fit in. 

can you stop it

Please remember that he's the best second grader in the country. 

Yeah, should just pour him a strong drink. 

But Max was a great president, no? 

@president_max

In terms of strength of play, there's no question that Steinitz was the weakest world champion.  Lasker was worlds beyond him, and every champion since then has been around Lasker's level or only slightly worse.  Euwe's form before WWII was much stronger than after, the talk here about him is akin to judging Jose Raul Capablanca by his results from 1938 onwards (after he suffered a stroke).  Euwe might have been a half-step down from the Lasker-Capablanca-Alekhine standard, but you can easily throw Botvinnik, Smyslov, and Spassky into that category.

In terms of judging character, there's a case to be made against Alekhine, Fischer, and Botvinnik.  All of them said and did things which are worthy of criticism.  Alekhine and Fischer had cause to hold a grudge (not that it justifies everything they said or did), but it's clear that their bitterness led both of them to a pretty dark place.  Botvinnik was a staunch Stalinist, so it's doubtful he had any kind of moral sense to begin with.  The rest of the group seem to have been reasonably decent human beings.

Dsmith42: Yes, and when Euwe finished solidly rock bottom in the world championship tournament in 1948, he was already 47 years old, Botvinnik was 10 years his junior, and the rest of the field even younger.

Totally agree with the character issues with regards to Alekhine, Botvinnik, and Fischer (with the caveat that Fischer probably was of unsound mind, from the mid-70s onwards).

As for Botvinnik's playing strength, I would actually go as far as to say that he's the most underrated of all world champions. He proved himself to be absolutely top class in the 1930s, basically lost most of his prime years to World War II (but still showed convincing results whenever he played), and then was to all intents and purposes an amateur (working as an electronics engineer). Between the WC tournament in 1948 and the WC match in 1951 he didn't actually play a single competitive game, and still managed to fend off Bronstein. A Botvinnik in regular competition would most likely have defeated Bronstein easily. He was head and shoulders above the rest at the end of the 1940s. As for his matches against Smyslov and Tal, he was already past his prime and played his last WC match aged 52. Lasker was 53 when he lost to Capablanca in 1921. There's no coincidence that Soviet coaches made their pupils study Botvinnik's games, and Alexander Kotov is full of praise for him, and rightly so. Anyone studying his game collection is bound to improve his/her positional play immensely.

Strongly disagree with DSmith that Steinitz was the weakest world champion. Besides being arguably the greatest theoretician in the history of chess, he was also an incredible player. When he faced Lasker in 1894, Lasker was 32 years(!) his junior. I played through the games of that match, and was surprised at how often Steinitz outplayed Lasker during the first half or two thirds of a game, only to throw away his advantage at the end through some crude oversight. The burden of age.

Before that, steinitz was undefeated in match play for over three decades, and those were matches against the strongest players of the time. During his heyday Steinitz was the greatest player in the world. A truly great champion!

Steinitz has something to teach all of us.

I think it was Dvoretsky who said that modern chess basically began with Steinitz.

euwe, steinitz and smyslov

     It's really difficult to compare the strength of players from eras a century apart. All world champions were the best player in the world in their own time. So I take the "worst world champion" to mean the person that behaved the worst during their reign--in chess matters, not their personal life.

     In that sense the worst were Fischer and Alekhine. Fischer in essence quit chess the moment he won the championship. He played no games, wrote no articles, commentaries or books, held no exhibitions or simuls. He behaved like a child throwing a tantrum when the world chess community wouldn't change all the rules of the championship match to be whatever he wanted. He did nothing during his time as champion to publicize the game or make conditions better for players despite complaining for years that such things needed to be done by those running the chess world. And finally, after complaining for years how the Soviets were manipulating top-level chess, he just handed control of the world-championship match back to them.

     Alekhine just treated the world championship as his meal ticket. He refused to play anyone he wasn't sure he could beat, extorted fat appearance fees from tournament sponsors by promising a match with the tournament winner only to refuse to honor his commitments, and was publicly drunk and obnoxious throughout his first match with Euwe, making the world see the world chess champion as a buffoon. Chess players and organizations worldwide were happy to have FIDE take charge of the world championship to make sure such things did not re-occur.

Fischer

Alekhine and Fischer.

Euwe
http://www.chessmetrics.com/cm/CM2/PeakList.asp 

No offense to him as he's a very talented player who fairly won his title (though it was split at the time) but I believe Ruslan Ponomariov is the worst because if you go past the fact he won the championship, he just seems like an average top player and little more. Euwe, Khalifman, and Kashimdzhanov also come to mind though all the players in my comment are still great and worthy of respect.