The United States do recognise God as extant, separation of church and state or no- he’s mentioned on our money.
You don’t have to worry about jurisdiction, either. You can sue anyone in a US court provided you can show the judge that whatever injury you’re suing over happened on US soil.
So sue away.
owlofcreamcheese: Would it be a huge decision? Imagine that the plaintiff didn’t have the resources to go through with an appeal, and that the local paper’s court beat journalist was tied up with delivering feature stories on a complex murder case. I can easily imagine the decision sitting in a file cabinet manned by underpaid civil servants, lacking any reason to be drug out as precedent.
And since when is atheism a religious doctrine?
dutchboy: Citing a phrase on American currency in court is flimsy. The judge would have to stifle a laugh, probably, and would dryly tell you to place your dollar in your pocket and come back when you have real evidence that the US government accepts God’s existence.
This nails it, in my opinion. You an only sue persons (real and legally created ie corporations).
You can no more sue God than trees, cats or ideas.
Theism is the belief, despite lack of conclusive evidence, that God exists. Atheism is the belief, despite lack of conclusive evidence, that God does not exist. Either is exactly as much a religious belief as the other.
Would there be a stronger claim for jurisdiction in Israel? Or would they have to rebuilt the Temple and Tabernacle first?
If God was served with papers and appeared in court, would he swear on the Bible or affirm in His own name? Suppose He scoffed at the Bible offered, citing its inaccuracies, and was pressed to affirm instead? Would functional designations like “Lord of Hosts” or “God, thy Father” do, or would He have to state His name – His holy, secret name? If He refused to divulge His secret name, He could be held in contempt of court, no? 
If the anti-lawerly supposition that “there are no lawyers in Heaven” is true, would God have to make do with a court-appointed lawyer or represent Himself? Being omniscient, He could probably do a good job the latter. But as the saying goes, “anybody who represents himself has a fool for a lawyer,” and being omniscient, omnipresent, and omnipotent, God could never be anybody’s fool. Ergo, God could not represent Himself; or if He did, it might put Himself and/or all creation at risk of non-existence by unholy paradox [see Adams, Douglas and Smith, Kevin].
If a judgement was returned against God, could plaintiff collect? Does God have any money or property? God is believed by many to have some wealth, although not necessarily filthy lucre per se, or any currency that is understood to be an instrument of the Devil. Perhaps God had a little money left over from his one known stint of lawful employment [carpentry] which he practiced as a young man. Said funds, constituted in silver coin and compounded annually for almost 2000 years, could today be a sizable sum indeed. However, even if God has money, His holdings are widely believed to be less than that of those affluent people who are said to be “richer than God”.
God is believed to be the sole owner and proprietor of “Heaven,” which is believed to gaudily decorated with innumerable quantities of gold and precious jewels, and probably a prodigious amount of frankincense and myrrh, as well. Perhaps a successful plaintiff would have to resort to filing a lien against Heaven.
Should God balk, file numerous trivial appeals, or otherwise stall on payment, the plaintiff might turn over the matter to a collection agency. Alternately, the plaintiff might negotiate a terms of an arbitrated settlement with God, for an amount acceptable to both parties. God might well claim penury, however.
Said terms would be, ahem, “pennies from Heaven”. 
Could one not sue a God and churches as co-defendants?
Gives a whole new dimension to the term “Judgement Day.”
Not in a US court. If a US court were to rule that the Pope of Rome had unique status as specific “representative” of God, said court would then be ruling on the status of a specific religion in violation of principles attached to the First Amendment of the Constitution. It is true that the First Amendment only specificaly restricts Congress from establishing a religion, but in general it would probably be considered highly questionable even in the current US Supreme Court for a judge to establish (in the Constitutional sense) a religion.
Plus, the Holy See is a foreign soverign, and could claim soverign immunity in the U.S. courts.
[nitpick]Vatican City is a soverign recognized by the U.S. government and entitled to soverign immunity, not The Holy See. They’re two separate concepts and, I think they’re not even geographically congruent.[/nitpick]
–Cliffy
No, at least not how the terms are actually used. In this case, devolving them to Latin roots isn’t really useful in determining their actual meaning.
[ul]
[li]Theism: What you said. It’s the belief in a deity (or deities) without evidence. Being a theist (without any further specification) can mean that you don’t ascribe any properties to that (or those) deity (deities), but I don’t think it has to.[/li][li]Atheism: Being highly skeptical of any religious claims, more specifically not accepting on faith the precept that a deity or deities exist. This is not the opposite of theism (which may not have an exact antonym in English), but the opposite of religious faith.[/li][/ul]
Why do I care? Well, people claiming that atheism is a religion are usually trying to convince me that I believe something I don’t actually believe, to wit: there is no deity. I do think that, but I don’t accept it on faith, any more than you (as a physicist) accept gravity on faith. There is a very useful difference there.
According to the CIA World Factbook, the two terms are interchangeable: