Bob Leverone/Associated Press

Sometimes, getting to the Super Bowl is the easy part. The harder task is for teams that have reached the NFL's pinnacle to stay there—to wedge their championship window open.

The Carolina Panthers are discovering that in 2016, facing the sort of tough decisions that led to the departure of cornerback Josh Norman.

And in re-signing offensive lineman Ryan Kalil on Monday, Panthers general manager Dave Gettleman stayed true to the philosophy that explains why Kalil and defensive tackle Star Lotulelei are still in town but Norman isn't.

So far as the Panthers are concerned, football is trench warfare, and they aren't letting go of the players who help them win there.

As Rand Getlin of the NFL Network tweeted, Kalil and the Panthers agreed to terms on a two-year extension worth just under $17 million. Most of the money is guaranteed:

Gettleman told Jonathan Jones of the Charlotte Observer that it was a no-brainer to lock up Kalil, whose contract was set to expire after the 2016 season:

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Ryan is still playing at an extremely high level and was very deservedly an All-Pro again in 2015. The other part of this is that Ryan is a great leader. In 2014, he was instrumental in keeping that offensive line group together. That group had a lot of young players and there were moving parts because of injuries, but Ryan helped them maintain their confidence and that was a big part of us winning five of our last six games. On and off the field, Ryan is a pro’s pro and we’re all very excited about this.

It isn't hard to see why Gettleman feels the way he does. Per The Observer, Only one offensive lineman in Panthers history has played more games for the team than Kalil. He's the foundation of a Panthers' front that paved the way to Super Bowl 50 in Santa Clara, California, last year. Kalil ranked fourth among NFL centers in 2015, per Pro Football Focus.

Those aren't the sort of players you let even reach free agency, much less walk out the door.

Especially if they are key contributors in the aspect of the game you believe is most important.

As Greg A. Bedard of Sports Illustrated wrote, Gettleman made no secret of how he intended to build his team when he took the job in Charlotte in 2013.

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"Big men allow you to compete," Gettleman said. "We're certainly going to look at the big hog mollies."

Gettleman told Bedard that his years in scouting taught him something: In his mind, at least, football games aren't won with speed and finesse; they are won with brute strength and power at the line of scrimmage:

Tom Coughlin made a great statement to me fairly early when he came in [as Giants coach]: Big men allow you to compete. And the more you look at it, the more you watch film—I was a pro [personnel] guy for 15 years, all I did was watch film—and it’s true. If you’re not strong on either side of the line with the big guys, it’s going to bite you. It’s going to cost you. That was the one thing I knew we had to do.

One thing is for sure: Gettleman practices what he preaches.

In this offseason alone, Gettleman has prioritized keeping both his offensive and defensive lines intact. Per Max Henson of Panthers.com, the team brought back veteran Charles Johnson (arguably Carolina's best defensive end) on a one-year deal Gettleman called a "win-win:"

In these situations, you always want to be in a win-win—he wins and we win. It was important that we give Charles that opportunity. At the end of the day, when you sign a contract, you want to walk away happy. You just saw the smile on his face. What this deal signifies is Charles is a man of his word and in his heart he bleeds Carolina blue.

As Joseph Person of the Charlotte Observer reported, the team also picked up the fifth-year option on Lotulelei, another decision Gettleman said was easy to make:

"He’s done everything we wanted. Star has not disappointed by any stretch of the imagination and he’s getting better. He’s earned this. I’m excited we’re going to have him around for two more years."

Bob Leverone/Associated Press

Of course, in today's NFL, the salary cap dictates that for every player you pay, there's another you can't. For the Panthers, that was Norman, who they originally slapped with the franchise tag only to then rescind it and watch him follow the money to the nation's capital.

While speaking to Mike Florio of Pro Football Talk, Gettleman didn't begrudge Washington giving Norman his mega-deal. He simply maintained that it runs contrary to how he views team-building:

Well, I don’t want to talk for any other team. You know, they were willing to give Josh that kind of a deal. God bless them. For us, it was a matter of resource allocation. Everybody has to make decisions for their club. I’ve said this a number of times, and I think people are probably tired of hearing me say it, but I’m going to step back and make the decisions that are in the best interests of the Carolina Panthers, and when you sign a player to a deal of that magnitude, it’s not done in a vacuum. Nothing is done in a vacuum, every decision every general manager makes has a domino effect and you’ve got to decide how you want your dominoes to fall.

Once again, Gettleman was true to form. When cornerback Captain Munnerlyn hit free agency, Gettleman let him walk. Same with safety Mike Mitchell. Granted, neither of those players was of Norman's caliber, but the Carolina defense was able to reload both times.

Of course, one particularly large task remains unfinished. One round after drafting Lotulelei in 2013, the Panthers selected Purdue defensive tackle Kawann Short. And after racking up 11 sacks for the Panthers and grading as PFF's fourth-ranked defensive tackle in 2015, Short is on the verge of a massive payday.

Bob Leverone/Associated Press

As Bill Voth of Black and Blue Review reported, Short is expected to be a no-show at the upcoming mandatory OTAs and possibly the following minicamp as he postures for a new deal. However, Short's statements in May didn't seem to indicate a man truly worried about his payday:

"If it happens, it happens," Short told Voth. "We haven’t focused on that. We’ve still got a lot we need to do. I put myself in a position, but at the same time, I’m not where I want to be. We are not rushing the issue."

Short has good reason to be confident. With nearly $30 million in cap space, according to Over The Cap, the Panthers have plenty of room to re-up him. Gettleman told ESPN.com's David Newton back in March, "nothing would make me happier" than keeping his class of '13 tackles together for years to come.

It stands to reason that will happen. It fits his modus operandi: load up on "hog mollies," (including 2016 first-rounder Vernon Butler), keep them in the fold and build a team that's signature trait is the ability to punch opponents in the mouth.

Given the success the Panthers have had since Gettleman took the reins, it's hard to argue with the method.

Gary Davenport is an NFL analyst at Bleacher Report and a member of the Fantasy Sports Writers Association and the Pro Football Writers of America. You can follow Gary on Twitter @IDPSharks.