What initiates a court/judge to block things like immigration that they have recently. Do people first present a case to the court?

So why cannot people bring a counter complaint to the court to open an action.

Its called judge shopping. They seek out a friendly or favorable judge and bring the action where it will receive what they think is a favorable ruling. One low life judge, the entire country suffers.

^^^

exactly - they seek the lowest pond scum judge they can find that sympathetic to their cause, he's likely slipped a few bucks and he issues his 'decree'

judges like this are the lowest life forms on the planet they're not interested in justice or the country, they're looking for a headline for their scrapbook

Since neither of the other posters actually answered your question, I'll take a stab at it.

I'm not a lawyer, but my understanding is that any such action has to be brought by someone with standing, or someone affected by the issue. For example, in the case of immigration law someone at risk of deportation could have standing to bring a suit or request an injunction to block the action. They would provide the court with evidence that such an action would be illegal/unconstitutional.

So in this case, the US Government would be able to counter the suit/injunction in court, presumably by calling witnesses or entering evidence saying why the action is legal/constitutional.

The judge would then determine who's right, based on their interpretation of the law (this is usually where issues/complaints crop up).

The losing side then has the option of appealing. The appelate court can either vacate the lower court's decision (i.e., cancelling it), affirm it (i.e., let the decision stand), or send it back to the lower court to be re-tried. Potentially, it could work it's way all the way up to the US Supreme Court.

My terminology may be off, but I think I have the basic concepts covered. Hopefully some of SF's legal eagles will come in and clarify things or correct me if I'm wrong.