Until the mid-nineteenth century in the United States, cohabitation was sufficient to prove the validity of a marriage. Unmarried cohabitation was virtually non-existent, and single parenting or bearing a child out-of-wedlock was a social taboo. As more states began to require a certificate to marry, marriage licenses assumed the additional role of outlining the dispensation of benefits. Surviving spouses were only automatically guaranteed benefits if the marriage was legal and recorded by the state. Today, all 50 states require a license to marry, though the steps required to obtain a license can vary.
Age
The first step in obtaining a marriage license is to meet the state's minimum age requirement. All states impose some form of age restriction. In most cases, the age is 18, but some states offer exceptions for minors if a decree is issued by a judge. Obtaining a minor exception requires the permission of the parent or guardian of the intended. In some states, like Arizona and Idaho, only parental consent is required for minors aged 16 or 17 at the time of application, but younger applicants must be issued an order from the court.
Relations
As of 2010, no state allows the marriage of close blood relatives. Many states do allow first cousins to marry, but in some cases, there are restrictions. Often, if a cousin-couple is of reproduction age, the marriage is disallowed. Others states will allow the marriage of fertile cousins only after both parties undergo genetic counseling. The counseling sessions explain in detail the types of genetic deformities and conditions that could result in children born of family members.
Application
A formal application for a certificate of marriage must be filed with the clerk of the county court in which the couple is living. If the couple is located in different county's at the time of the marriage, the certificate is issued in the county in which the wedding will take place. The application process, as of 2010, is fairly uniform among the states, though some do still require a physical exam or blood test to rule out the presence of venereal diseases or infectious diseases like rubella or tuberculosis.
Along with the application, each partner must submit valid identification. Rules governing what constitutes valid ID vary by state, but generally a driver license or state issued ID card is sufficient. Previously married people are required to provide proof of dissolution, though that requirement is waived if the divorce was final more than five years before in many cases. There is a fee required at the time of application.
Waiting Period
Twenty states impose a waiting period between the date of application and the date of issue. The length of time varies by state between one and six days. The objective is to allow a cooling-off period and prevent snap decisions that could possibly end up in divorce court or the annulment offices.
Witnesses
Once the ceremony is complete, one or two witness signatures are required and the completed form must be filed by the officiate of the ceremony. Once the state processes the completed document, a state-certified copy is sent by mail to the new couple. This certified copy is needed to complete a name change with banks, the Social Security Office and other personal accounts.


