The Patriot Act extension passed by Congress this week did not become the law of the land. It is void and without effect.

So may argue some future defendant whose conviction rests on evidence gotten under Patriot Act powers during the extended period Congress sought to establish in the bill it passed this week.

President Obama is at a meeting in Europe, so he had the bill signed by auto-pen. Representative Tom Graves (R-GA) has written a letter inquiring of the president whether he was presented the bill and truly intended to sign it.

Article I, Section 7 of the Constitution says:

Every Bill which shall have passed the House of Representatives and the Senate, shall, before it become a Law, be presented to the President of the United States; If he approve he shall sign it, but if not he shall return it…

Is presentment and signing a quaint formality? Something to put aside in light of modern technology and time-constraints? Or is it an important step in the law-making process, to be executed quite literally without deviation from past practice?

The answer lies mostly in consideration of what a signature is, and what it does. I looked into signatures, among many other identifiers and security techniques in my book, Identity Crisis.

Wikipedia has a definition of “signature” that’s good enough: “A signature is a handwritten (and sometimes stylized) depiction of someone’s name, nickname, or even a simple ‘X’ that a person writes on documents as a proof of identity and intent.” Key words: identity and intent.

In the world of identification and security, a signature is classed as a “behavioral biometric identifier.” That is, it’s a product of a given person’s bodily action that is distinctive enough to create strong evidence of the person’s presence.

A signature does many things, and inferences spill out from the presence of a mark on paper that is sufficiently similar to other marks made by a particular person. Because it’s left on the paper, a signature indicates that the person was in the presence of the document. This means in most cases that he or she could review it and had the opportunity, barring some exigency, to affirm its accuracy and completeness. By long-standing custom, absent duress or fraud, the signature indicates the giving of one’s assent or the placing of authority behind the content of the document. A signature supplies evidence—imperfect, to be sure—that a given person approved a given document.

Does a signature by auto-pen create the same inferences? Almost none of them. To know that President Obama indeed meant to affirm the bill, one would have to investigate how he was apprised of the bill’s content. Were there security measures in place to ensure that the communication about the document and the giving of assent were not altered or forged in transit from Washington, D.C. to Europe? One would need assurance that the controller of the auto-pen applied its mark to the exact document that the president was apprised of, and that no substitute document was inserted. All these problems are solved by bringing the person with authority into the same room with the document to manually apply the signature.

I haven’t a whiff of doubt that President Obama intended to sign the bill. The authority of the president and the gravity of bill-signing are such that I’m confident security measures were in place to control the security issues noted above.

But the question in a court case dealing with the presentment and signing requirement is not what happened with this particular bill. It is what should happen in all cases to help exclude the risks of fraud and duress in law-making—with much longer bills, for example, or some future circumstance when the president’s whereabouts or capacity might be unknown.

The authority of the president and the gravity of bill-signing actually cuts the other direction: The president should be in the same room as the actual document, applying his genuine signature to the artifact of a United States public law’s creation. It’s that important a function of the presidency.

Until biometrics and encryption are good enough that we can sign our mortgages remotely, it’s not too much to ask, having the president to sign legislation in person. If a criminal or two go free in the future because of the inadequacy of the process here, it will be worth it for the small security against fraudulent passage of legislation in a future full of uncertainties.