English Translation
I wish that I could do more.
Why is ‘to wish’ in the past tense here?
I wish that I could do more.
Why is ‘to wish’ in the past tense here?
Konjunktiv II is about describing hypotheticals. It roughly matches up with the subjunctive in English, although the subjunctive is slowly dying out of the English language:
Ich wünschte, dass es wahr wäre = I wish that it were true
In modern English, it’s common to (incorrectly) use the indicative there (I wish that it was true), but never mind. Konjunktiv II in German has more of an effect on verb forms than the subjunctive does in English, and so we see that sometimes verbs appear to be in the wrong conjugation, but they aren’t. It’s just a different verb mood (Indikativ versus Konjunktiv II in German, indicative versus subjunctive in English).
I wish that you had told me = Ich wünschte, du hättest es mir gesagt (or “I wish you would have told me”)
I wish I could have done more = Ich wünschte, ich hätte mehr tun können (or “ich könnte mehr tun”)
We’re in Konjunktiv II with these examples because we’re describing a hypothetical.
In German, if you know that your wish can’t (currently) be fulfilled, then Konjunktiv 2 applies to the verb “wünschen” too. English does not apply the same logic.
We are talking about unfulfillable wishes here, therefore we need Konjunktiv 2. Be careful: “wünschte” isn’t (in this case) the past tense of “to wish”, it’s the Konjunktiv 2. The past tense and Konjunktiv 2 of “wünschen” just happen to be identical.
Let’s look at some examples:
You know your wish can be fulfilled:
You know your wish cannot be fulfilled:
Your wish is unfulfillable, but you are not aware of that (as young children are, for example):
So whether you use “wünschte” or “wünsche” depends on whether you yourself are aware that your own wish can’t be fulfilled.