Never mind, other page, found it. Choose an opponent is the targeting, it is not the sole effect. Both sentences are the effect. Targeting something and then failing to be able to succesfully resolve the effect causes problems about whether or not the card can be triggered based on the specifics of wording. If Able as the rule is currently written would allow for it to be triggered assuming the targeting restriction is met.

I want to be clear, I'm not trying to defend the "if able" definition, I'm simply trying to relate how it effects the game.

And at risk of another moderator warning me about personal correspondence, Damon didn't seem particularly thrilled about the definition either. If I had to take a guess it is something he inherited that he doesn't believe improves the understanding of the game as currently written. (I want to be clear he didn't say this, I'm reading between the lines)

Whether he clarifies the definition or changes the definition is anyones guess, but he did say he was going to examine it since it is causing so much confusion.

Penfold said:

However, this is what I thought was a general rule: As long as you selected a valid target, you can trigger the effect.

It doesn't matter for this purpose if the effect actually 'does nothing' or not.

If it's not stated anywhere explicitly it can be inferred from other FAQ answers, e.g. the one about Y'Golonac (readying ready characters…).

So, I'd say, in this example, 'if able' doesn't actually change the card text's meaning. If anything, it's just an attempt to clarify the meaning (which unfortunately backfires).

I'm glad to hear that Damon is not exactly happy about the 'if able' clause either!

I agree that more often than not the term "if able" does not actively change how we would have ruled on how the card was played anyway, and it does look like an attempt to make things more clear… and yes I do believe that it causes at least as much confusion (at least to the people here) as it clears up. This is why I am a big proponent of cards being worded in a specific way, and using the timing charts and game defined terms (like Action: and sacrifice) to carry across everything, even if it means players have to stop for a moment and parse a complicated card rather than trying to use common usage phrases and then defining them in a specific way or including extra language to make things more clear. Meh. I'm not the designer, past, present, or future so it I don't get a vote.