A Question RE: Interpretation of Jeremiah 12

As I read this chapter today, a basic question springs out to which I (currently, at least) do not have a satisfactory answer. It is the question of just who "the wicked" are that Jeremiah speaks of in vss. 1-4. Upon reading it,I wonder if Jeremiah is not referencing other nations that are oppressing Judah. If so, then it seems to make sense to me why God would respond to Jeremiah's call for Him to punish "the wicked" by saying things like:

If racing against mere men makes tou tired, how will you race against horses? If you stumble and fall on open ground, what will you do in the thickets near the Jordan? Even your brothers, members of your own family have turned against you. They plot and raise complaints against you. Do not trust them, no matter how pleasantly they speak. Jer. 12:5-6

In essence, I'm asking if the first four verses are Jeremiah's call for"justice" against the "wicked" oppressor nations, and the following eight verses are God replying that what is happening to Judah is justice for the past crimes of the chosen nation.

It seems to me like getting the appropriate message from this text is dependent upon identifying who is being talked about. Any help or insight in this regard would be appreciated.

------------------------------------------------------------------------------------

Since last week's post, I've heard back from a former professor of mine, Mark Hamilton. Dr. Hamilton is a specialist in the Old Testament, and was kind enough to point out a possible problem with my interpretation. In 1:4, the "people" say "the LORD (or Yahweh) doesn't see what's ahead for us." Because Gentile nations would be less inclined to use the personal name of Israel's God, he tends to assume that verses 1-4 refer to Judah's sins. However, Dr. Hamilton did point out that--like many OT prophetic oracles--it is difficult to pin down a chronology/and identify all the players here.

I think the interpretation I originally proposed COULD still work. I suppose it depends on whether one interprets vs. 4 to be the ACTUAL words of the (supposedly Gentile) people, or simply a paraphrase of their sentiment expressed in the language of Jeremiah.

A third option that occurs to me is that perhaps verses 1-4 refer to Israel, rather than Judah. Remember that Jeremiah's ministry takes place post the division of the Israelite kingdom. As always, any further reflections are much appreciated!