Second Conditional - Past Tense or Past Subjunctive

Hi there

My question is about the second conditional. This grammatical construct refers to unreal situations in the present.

An example is: "If I had a million dollars, I would buy myself a nice car."

As you can see, this construct contains an if-clause expressing an unreal condition for the statement in the main clause.

The second conditional always has would and the bare infinitive in the main clause.

The subordinate clause contains the "if" and then either, and that's my question, the past simple or the past subjunctive. It depends on the source which of the two forms is mentioned.

I now would like to know which of the two grammatical forms it actually is, the past subjunctive or the past simple.

I am aware that it might be the case that both forms differ only very slightly in modern english, so it does not make a difference in speaking anyway.

Nevertheless, as both of them are said to be part of the second conditional alternatively, it gets clear that they are not the same.

My questions are now:

Is the second conditional formed according to the following pattern:

If+past subjunctive, would+infinitive

OR

Is it formed like that:

If+past simple, would+infinitive.

If it is the case that it is the past subjunctive, why is it so widespread to call it past simple instead? Isn't that very confusing although both forms are more or less identical?

Looking forward to your answers.