This is a particularly difficult area for immigrants to use when gaining entry into in the United States. Those with green cards and non US spouses are able to bring their family to join them, but not until they have lived through an extensive, many year delay. During this delay, the family is separated. This process may take up to five years unless the non-card holder applies for a visa for themselves. Due to the long wait, many green card holders decide to become US citizens – usually also a five year wait – and then opt to sponsor their family. This still means that the family is separated for the duration of the process.
Green card holders may have challenges to face. For instance, those visiting and those who are not immigrants on temporary visas may sponsor their spouses to live with them, but they cannot work in the US.
US citizens may sponsor their spouses as non-immigrants and they may then convert to immigrant status; a process that generally takes 12 months or less. The advantage is that the spouses are in the US during the process, unlike the spouses of green card holders.
At one time the V visa, introduced by President Clinton, let green card holder’s families unite. This visa no longer exists, and while there is some indication the Congress may try to resurrect it, no action has been taken to date.