The case for open borders is four-fold:

• Moral case: A number of different meta-ethical frameworks: libertarian, utilitarian, egalitarian, and other hybrid and independent frameworks (such as the bleeding-heart libertarian case, conservative and small-government case, and cases based on religious philosophies), all point in the direction of open borders.
• Practical case: There are a number of concrete, practical benefits of open borders: to the migrants themselves, to the immigrant-receiving countries, to the immigrant-sending countries, and to the world at large.
• Second-order case: Objections to immigration can be met with keyhole solutions. There are also various arguments from authority that point to open borders.
• Country-specific pro-immigration arguments include the US-specific pro-immigration arguments.