Evaluating defense isn't exactly the easiest thing to do. It's part eye test, part advanced metrics that we all point to while maybe 3% of us actually understand what the hell they actually mean, part who else is on the floor, it's not really an exact science. Elite defense is just something you know when you see it. Now all four of these dudes are monster defenders in their own right. Some have the built in name recognition as elite perimeter defenders, others are new to the scene and every bit as dominant. That's what makes this such a tough question in my opinion. You have to remember that we're talking about right now, right this second in 2020. Not what someone may or may not have been in previous years. Before we officially cut one of em, let's make a case for each
Defensive stats: 105 Drtg / 2.0 Defensive Win Shares / 1.1 DBPM / 2.2 STL% / 1.4 BLK%
For some time now, when you talk elite two way wings Paul George is high on that list. Just last season he made All NBA Defensive First Team, but I don't think he's making it in 2020. This is by far his lowest Defensive Win Share season, and who knows maybe part of that is because he plays next to Kawhi, but at the same time the Clippers defense is basically the same when he is on or off the court. Opponents FG% go from 46.6% on average to 47.8% when guarded by George this season, his STL% is the lowest its been since 2015 (tied for lowest in career), and I'd say you can put George comfortably at 3 positions, and a 4th if the opponent is going small at PF.
Defensive stats: 108 Drtg / 2.5 Defensive Win Shares / 1.3 DBPM / 2.4 STL% / 1.6 BLK%
Jimmy Butler is another guy who relies a lot on his defensive reputation than actual production in 2020. He's another guy that has made All NBA Defense teams over the years, but none since 2017-18 (2nd), and I don't see that changing in 2020. To his credit, this season opponents FG% dropped from 45.5% to 42.0% while being defended by Butler, but his DWS numbers aren't close to what he was putting up in CHI which is what I feel like a lot of people remember Butler from when it comes to defense. He's still very good don't get me wrong, but Miami Heat Butler is certainly not the defender that Bulls Butler was.
Defensive stats: 107 Drtg / 2.4 Defensive Win Shares / 1.3 DBPM / 2.4 STL% / 1.5 BLK%
Marcus finally made his first All NBA Defensive First Team last season and is backing it up big time this year. He is actually someone of the four that should make another All Defensive team, most have him repeating his first team spot. He'll even get some DPOY I'm sure. While his defensive metrics are similar to the previous two, there's really one big difference between Smart and basically everyone on this list. He defends ALL FIVE positions at an extremely high level. Not just when opponents go small either. Doesn't matter who it is, Smart puts down clamps. Opponents go from 45.1% to 42.7% while being guarded by Smart, and I think at one point he had matched up against centers on 133 possessions and given up a total of 9 points. It makes no sense yet perfect sense at the same time.
I will say this though, he's not perfect. Certain styles of guards give him trouble and this is more about perimeter defense than post defense. It's OK to say he's a defensive monster but at times struggles with staying in front of super quick and shifty guards.
Defensive stats: 105 Drtg / 3.2 Defensive Win Shares / 2.4 DBPM / 2.9 STL% / 1.4 BLK%
Let's call it like it is. Ben Simmons is the best defender of this group, and I'm not sure it's really up for debate. Once again, credit to me for not being biased and using both reason and truth. He guards every position for the most part, and the work he's done on superstar level players cannot be ignored. Opponents go from 46% shooting to 41.3% when guarded by Simmons which is by far the biggest drop of anyone listed, he leads the league in steals, and of all the players in the league, Simmons spends the second most time guarded All Stars
Sure he's still someone with major holes offensively, but on the defensive end he's the very definition of a stud.
So who am I eliminating? Well it sure as shit isn't going to be Marcus Smart. Not sure how that thought would even cross your mind. It's also certainly not going to be Ben Simmons, so that leaves us with Butler vs George. Two guys who were nails these last few years but have started to drop a little bit. I think I have to go George, if not for the fact that opponents don't shoot any worse while being defended by him and his advanced metrics have slipped.
So sorry PG13, hate to do this to ya but you gotta go.