Translation:We are going to defend our country.
The infinitive verb (defender) after vamos a gives away the future (we're going to). If it were a noun after vamos a then it would be "we go to". (Vamos a la iglesia los domingos = We go to church on Sundays (or every Sunday).
Of course, it's still too simplistic to just consider what I've just said, and context is still king. "Vamos a la iglesia
el domingo" is still "We're going to church on Sunday" because "el domingo" removes the sense of the action being habitual that was present in the sentence above with "los domingos".
At least, this is according to my book Easy Spanish Step-by-Step by Barbara Bregstein.
nope, actually it may give the sense of a habitual action, (a native speaker would underestand it like that) the thing is that you cannot say ''vamos a la iglesia domingo'' (without the artcle el) so you have to use an article. unfortunately in this case it is abiguous, so it depends on the context or in the tone of voice. To make it clear, and to mean that it is not habitual, you can say '' Vamos a la iglesia este domingo''
Firstly there are two main types of future tense - future and near future. With the structure voy a + infinitive (verb), the English translation is "I am going to (verb)". Just to say "we go" doesn't really fit with this English structure. It is more of an evolutionary irregularity in our language (we shorten and change structures to sound more natural). So basically, only an English error on your part; the language has so many variations for just one Spanish phrase.