もう議論はよしましょう。

now; soon; shortly; before long; presently; already; yet; by now; (not) anymore; further; more; again; another; the other; interjection used to strengthen expression of an emotion (often exasperation)

argument; discussion; dispute; controversy

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

to cease; to desist; to cut it out; to lay off (an activity); to drop (a subject) to abolish; to resign; to give up