word choice - pretend, imagine and suppose

An article about the msnbc political show with Chris Hayes is titled :

Let's pretend we had a functional Congress.

The way I read this title is that it says that we are to pretend that we have a functional Congress now, as opposed in the past. Hypothetical past tense is used with "suppose" and I guess that "Let's suppose we had a functional Congress" would be as acceptable if not preferred to "Let's suppose we have a functional Congress", but what about the use of "pretend" and "imagine" with the past verb form the same way?

In this sentence I'd understand that either pretend, suppose or imagine would imply that we don't have a functional Congress, but for the sake of argument we are imagining a situation in which we have. By using any of these verbs in this sentence the inference would be that the fact of the matter is different, and the situation we are imagining, supposing or pretending to exist is counterfactual. "Had" in this sentence thus refers to current state of affairs and not to the Congress in the past, that is, "had" is used to convey a hypothetical idea and not to place the situation in the past.

I understand that unlike suppose, verbs pretend and imagine are not normally followed by hypothetical past tense verb, but I find examples such as the example I cited or with "imagine":

Imagine if we had the McCarthy era right now.

Imagine we had a studio right now.

where the meanings of the three verbs seem to overlap, and I understand that the past tense verb following them can be rephrased as "we are imagining a situation in which something is true or is happening now" as opposed to imagining a situation that occurred in the past.