Update (May 17, 10:00 a.m. ET): This piece has been updated throughout to reflect the Boston Bruins' win on Thursday against the Carolina Hurricanes.

The Boston Bruins have advanced to the Stanley Cup Final for the third time in a decade. They swept the Carolina Hurricanes with a win Thursday night to earn the opportunity to play for hockey's greatest prize.

Although the Bruins have an undeniably talented roster of veterans and young standouts, there's a dark side to their march to the final: star Brad Marchand. His violent and immature antics on the ice — and the free pass they've gotten from hockey officialdom — taint the Bruins victory. More importantly, they tarnish the NHL’s effort to stand alongside basketball, football and baseball as the preeminent sports in the American pantheon, ones that elevate skill over goonery.

Star Brad Marchand's violent and immature antics on the ice — and the free pass they've gotten from hockey officialdom — taint any Bruins victory.

Marchand entered the off-season with a reputation for being one of the dirtiest players in the game. That image has only been burnished over the course of the playoffs. During Boston's second-round series against the Columbus Blue Jackets, Marchand punched a player in the back of a head after a scrum. In the series against the Hurricanes, he took a swipe at a player’s head with his stick, leading to an altercation that saw only the Hurricanes penalized. In neither case did he receive so much as a penalty — instead, he went on to lead all forwards with more than 19 minutes of ice time in the game against the Jackets. In the game against Carolina, the penalty the Hurricanes took led to a power-play goal for the Bruins.

If you are a fan of the Bruins, you love what Marchand is doing. If you are a fan of any other team, his outbursts are a symptom of a fundamental problem in the NHL: turning a blind eye when the difficult decisions needed to cement hockey’s place in the “Big 4” of American sports have to be made.

When it’s found itself under pressure, the NHL has opened itself to change. After labor strife forced the cancellation of the 2004-05 season, the league knew they had to win back fans. They made rule changes that benefited skilled players because they thought fans needed a new product to reward those who stuck with the sport after its absence.

The adjustments included making sure officials policed every violation by the book. A record number of penalties were called the next year. But when traditionalists complained that all the penalties meant much of the game was being played with one team having more skaters on the ice than the other, the referees started calling fewer penalties instead of taking the time to allow players to adjust. The game eventually reverted to its previous state.

A decade later, skill became the focal point once again as concerns over concussions grew and a public outcry pushed the league to address the issue. As a result, during the regular season, the rules are now generally applied and skill usually wins out. But then the Stanley Cup playoffs arrive, with the stakes at their highest and the room for error at its narrowest. On-ice officials become wary of having to make a call that can change the outcome of a game and start to allow a looser style of play.

A veteran like Marchand has exploited this, knowing he can get away with things that would be called instantly during regular matches. And even though the star player’s slightly less egregious actions during the regular season are often ruled out of bounds — he has licked opponents during fights and cross-checked players at their heads — the discipline, or lack thereof, is minor enough not to change his behavior.

The NHL has dealt with players who have become a problem in the past. When former NHLer Sean Avery attempted to get under the skin of an opposing goaltender by continually waving his stick in his opponents’ face, the NHL changed the rulebook within a day to ensure it didn’t happen again. The league showed that when motivated, it can act.

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Moreover, the NHL’s supposed desire to favor skill over brutality can only be taken so seriously given that the league still allows fighting. Punching a player in the back of the head a la Marchand isn’t okay. But two consenting adults can drop the gloves and grab each other’s jerseys while the fists go flying. Only once at least one player falls to his knees or hits the ice is the fight broken up by officials. The number of fights is falling (1.3 per game back in 1987 when the stats were tracked to fewer than 0.2 today), but still a part of the game.

The NHL's official stance is that fighting earns a five-minute penalty. But the fact that it's permitted at all while it’s been effectively banned from Olympic competitions is telling. The rest of the world has deemed that allowing two individuals to throw punches while observers look on has nothing to do with the game and shouldn’t be permitted. What does that say about the NHL?

The remaining playoff games provide an opportunity for the league to show that it deserves to be regarded as a marquee sport in 21st century America.

The old argument is that fighting is part of the game. It's tradition and built into the culture. But the culture has changed and the game is more exciting with highlight reels of dramatic goals rather than boxing matches on ice.

The remaining playoff games provide an opportunity for the league to show that hockey deserves to be regarded as a marquee sport in 21st century America. Given Marchand’s record, there is every likelihood that he will cross the line again. Officials must severely punish him, and the Bruins, this time.

Brad Marchand is a 100-point player. He should be celebrated and showcased for his skill and not his pestering. But without the necessary discipline, a simple Google search about the highlights of the Stanley Cup playoffs won't be topped with his or anyone else’s skills on display. It will feature mistakes and immaturity.