In each Turn of Mars Attacks you are given a choice of options (see page 6). The vast majority of the time you will be doing one of the first two, so we’ll focus on those for now. These choices are:

1. Activate up to two different models.
2. Activate one model and play a card from your hand. 

Put simply, do you choose quantity or quality? 

You can activate two models (quantity), or a single model and enhance its actions (or your overall position) by playing a card (quality).

Some people seem to be a bit confused by “play a card from your hand”. This means exactly what it says, and it refers to any card you play, not just Support cards. A couple of examples should make this clearer.

• If I SHOOT with a model and play a card to give him a bonus to that attack, then I have activated a model and played a card from my hand. There is nothing more I can do in this Turn.
• If I play a Support card and then activate a model, I cannot then play a second card from my hand to boost his action.

When it says (page 12) that “You may only play one card to modify each test and you do not have to play any” it is not changing the above rule. It is simply stating that there is a 1 card limit per test and this is optional. You must still obey the basic limitations explained above, and so if you have activated two models this Turn you have already chosen to deny yourself the option of using a card. Both rules are correct and both apply.

What’s important here is that this rule also applies the same limit to the player who is not taking a Turn. His response is also limited to a single card per test. This is important as the cards with the Skull icon that you play in your opponent’s Turn are not limited otherwise.