Learn Icelandic: Við vildum ekki að stjórinn þvingaði okkur.

The main verb is vilja (to want), which expresses a desire or will. When you want someone else to do something, the verb in the following að complement clause must be in the subjunctive. Because 'we' want 'the boss' to not do something, þvinga takes the subjunctive mood.

Why do we use the past subjunctive instead of the present subjunctive?

In Icelandic, the tense of the subjunctive clause normally agrees with the tense of the main clause. Since the main verb vildum (wanted) is in the past tense, the subjunctive verb þvingaði must also be in the past tense.

Doesn't þvingaði look exactly like the normal past tense (indicative)?

Yes, it does! For weak verbs in this category (like þvinga, kalla, or borða), the past indicative and past subjunctive forms are completely identical. You only know it is in the subjunctive here because the grammar rule for vilja að requires it.

Why does ekki come before the að conjunction?

The negation ekki modifies the main verb vildum. Because it belongs to the main clause ('We did not want...'), it is placed directly after the main verb and before the conjunction that starts the dependent clause.

Is okkur in the accusative or dative case in this sentence?