Marriages voidable nun pro tunc ("from now for then") are legal, but flawed in such a way that the law says they are not recognized. For example, if one spouse tricks or forces the other into marrying, if the spouses do not understand what they are doing at the time due to mental incapacitation, or if one spouse is impotent - these circumstances make for voidable marriages and are able to be annulled in most jurisdictions. However, depending on a state's laws, statutes of limitation for annulling voidable marriages can range from a few months to several years. The time frame usually begins with the date one spouse learned about the circumstance that makes the marriage voidable.