This site advocates radical open borders. However, many people make distinctions between different kinds of immigration, depending on the source and target countries, the time period involved, and the nature of immigrants. Some of these distinctions are discussed below:

• Legal versus illegal: Some claim that they have no objection to legal immigration, and want to see legal immigration liberalized and expanded, but they do object to illegal immigration. See also nomenclature for illegal immigrants and morality of violating restrictive immigration laws.
• High versus low skill: Some claim to support high-skilled immigration and opposed low-skilled immigration. Others claim to support low-skilled immigration and oppose high-skilled immigration.
• Then versus now: Some claim that open borders were suitable in a past era, but are unsuitable to the realities of the modern world.
• USA versus Europe: Some claim that Mexican immigration to the United States is okay, but Islamic immigration to Europe is not.
• Short versus long run
• Moderate versus radical open borders