§ 135.640 When objections that are grounds for demurrer may be taken

If someone wants to challenge a criminal charge because of a problem that's obvious just from reading the charging document, they usually have to raise that problem early by filing a formal objection called a demurrer. They can't wait and bring it up later in the case.

There are two exceptions to this rule. A person can still argue that the court has no authority to hear the case, or that the facts described don't actually add up to a crime, even after the early deadline has passed. These two arguments can be raised at trial, while entering a not guilty plea, or after a conviction when asking the court to cancel the judgment.

In short, most problems with a charging document need to be caught and raised right away. But questions about the court's power to hear the case, or whether the charge even describes a real crime, can be brought up later in the process too.