John Barrowman explains why Captain Jack never killed Hitler in Doctor Who

But he doesn’t just sit twiddling his thumbs. Instead, Captain Jack decides to fight in both World Wars, knowing the bloodbath he is walking into.

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Why?

“One of the things that defines Jack is his need to help humanity rather than himself. He would have gone back to help defeat the wrong and the evil that was going on in the war, just as he would have when facing The Families in the last series of Torchwood [Miracle Day],” Barrowman explains to RadioTimes.com.

“Although Jack didn't believe it himself, Jack was a hero. And Jack was always the swash-buckling hero to go back in to help people and save them. Because he was immortal, he could sacrifice himself for the good and the sake of others and then return to continue to do good.”

Who could argue that that's pretty darn noble of Jack? Using his super-charged indestructibility to save lives and help end some of humanity’s most horrible conflicts is one of the best things he could have done. No qualms here.

But dig a little deeper and a niggling question might pop up: why didn’t Captain Jack just kill Hitler?

Surely if Barrowman's character wanted to end the Second World War, this would have been a pretty good strategy – and, more importantly, it would make for great TV: we can definitely see Jack charm his way through the heftiest Third Reich security before bumping off the Fuhrer (preferably after paying homage to Doctor Who's classic “put Hitler in the cupboard” moment).

It’s not exactly as if Jack is averse to meddling with time at this point either. While the butterfly effect theory supposes that tiny actions have major reactions down the line, Jack is doing a lot more than killing a butterfly: he’s taking bullets for soldiers who would have otherwise died and – presumably – is killing quite a few German soldiers too. Entire future families are being created and destroyed by his actions.

Without a doubt, wartime Jack is already changing future events like there’s no tomorrow. So, why not kill off Adolf and save even more people?

“I love it!” Barrowman says with a laugh when we put this to him. “That storyline would have been a great storyline!”

However, Barrowman has his own theory as to why Jack resisted the urge to change history in this way: the writing wouldn’t allow it.

“The thing that made Torchwood and Captain Jack such a great character – and the stories of Russell [T Davies], in particular – was the fact that they mimicked what happened in the real world. [Jack killing Hitler] wouldn't have made sense because if he would have gone and killed Hitler, history wouldn't have been the same as what we were living today,” he explains.

“Jack couldn't kill Hitler because Hitler was always going to survive up to a point and do the damage that he did. If he'd have killed Hitler, we couldn't have written those stories that mimicked actual history.”

In other words, Jack couldn’t kill Hitler without seriously impacting the events of other Doctor Who stories – after all, the show’s continuity doesn’t keep itself air-tight, you know.

Of course, this is only Barrowman’s take. There are plenty of semi-plausible in-Whoniverse explanations too.

You could argue that Jack didn’t want to kill Hitler in case it screwed up future fixed points in time. Or that Jack would be creating a paradox – by killing Hitler and altering future events, he might never have jumped back in time in the first place. Hell, you could even blame it on the Time War.

The most convincing though? Four words: wibbly wobbly timey wimey. Case closed.