This card is essentially 2 ER to defend an additional time. Nothing special, but a fair rate for an extra defense. If you are already ready when you play this, it accomplishes the same thing as Indomitable or Desperate Defense which let you re-ready after defending. This adds the ability to defend if you are already exhausted, which is very niche but could come up if you want to exhaust for your first defense because you aren't sure you'll get the chance to defend again, or if you surge Exhaustion into Assault. It's hard to imagine doing anything too powerful with this, but as a way to defend some more, this is fine - especially in multiplayer where more attacks occur per round. The most obvious hero to play this card is Captain America for flavor purposes (though he can be a serviceable defender)
Defense.
Hero Interrupt (defense): When an enemy attacks, declare your hero as the defender without exhausting them.
Unless I am mistaken (and I really hope I am on this, or that it receives an FAQ/errata), but isn't the only effect of this card to put you in the way of an attack, like any "Hero Interrupt (defense)", while doing literally nothing else?
The text of the event specifies timing, so you can use it for any enemy attack (as opposed to some Defenses), but for all other intents and purposes, it only puts you in front of an attack, and nothing else. It doesn't say to make a basic defend without Exhausting, which I believe is the true intent of this card.
Take for example, the simulatenously released Cuts Both Ways, which for 1ER does exactly the same effect (defending), on the same trigger, with the upside of getting a point of Retaliate. And it's cheaper.
Someone sanity check me, please.