[Polybius]

No State shall, without the Consent of Congress, lay any duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact with another State, or with a foreign Power, or engage in War, unless actually invaded, or in such imminent Danger as will not admit of delay.

The only "compact" in this whole thing is the poor choice of that word by the author of this article. There is no "compact".

New Jersey is not saying, "We will do it if you guys do it."

New Jersey is saying, "We will do this and disenfranchise New Jersey voters in Presidential Elections because we really are that dumb."

[Anitius Severinus Boethius]

Sixth sentence of the article:

The compact would take effect only if enough states—those with a majority of votes in the Electoral College—agreed to it.

[Bob]

New Jersey is not saying, "We will do it if you guys do it."

Yes, they are. The law only goes into effect if enough other states agree.