Admitting the territories as states wouldn’t disrupt the balance of power in Washington
The United States administers five inhabited unincorporated territories: American Samoa, Northern Mariana Islands, US Virgin Islands, Guam, and Puerto Rico. Although the inhabitants of these islands are either US citizens or US nationals, they do not all have the same rights as citizens from states.
All five territories send delegates to the US House of Representatives, but those delegates are not allowed to vote on proposed legislation (though they may participate in other House functions, including committees). What if citizens and nationals of these territories were granted the same rights as citizens of the rest of the country?
First, consider American Samoa and the Mariana Islands. With populations of just under 60,000 each, their representatives to Congress would hold a lot of power compared to other states, where there is roughly one congressperson for every 700,000 people, and one senator for every 3 million people.
One representative for 60,000 people and one senator for 30,000 people from American Samoa and the Mariana Islands, making those individuals disproportionately powerful for their small constituency. Arguably, that is the Constitution’s protection of minorities at work, but there could also be legal challenges if the Supreme Court’s ruling in Reynolds v. Sims were expanded from state legislatures to the national legislature. There, the Supreme Court ruled that the 14th Amendment to the US Constitution requires that state legislative districts should be comprised of roughly equal populations if possible.
Guam and the US Virgin Islands would run into a similar population disparity for its representatives, with populations of about 100,000 and 150,000, respectively. Even the least populous state, Wyoming, has a population of nearly 600,000 people living there.
Puerto Rico, on the other hand, has a population of 3.2 million people, more than 20 states. Senators from Puerto Rico would represent less than the national average 3 million people, but there would be five representatives sent according to the national average of 700,000 constituents for representatives.
Adding five new states to the Union would make Capitol Hill look a bit different. There could be 10 new senators, and likely 9 new congresspersons. Because of the Permanent Apportionment Act of 1929, which apportions a constant 435 as the total number of seats in the US House of Representatives, these 9 new congresspersons for the territories cause some states to lose representatives based on census data.
Until the new census, however, there would be 444 seats in the House, because the reapportionment occurs with every census. This would increase the number of presidential electors from 538 to 557 and shift the victory threshold for the presidency from 270 to 279 electoral college votes, at least until the next census.
It is difficult to determine the political implications of all five of these territories were incorporated as states, because the politics in the territories are different from the politics in the mainland US. In Guam, for example, people vote only loosely based on party, and focus more on the candidates. The 15 member unicameral legislative body has 10 Democrats and 5 Republicans, but the issues Guam faces aren’t neatly Republican or Democrat, and this isn’t determinative of how Guamanians would vote in national elections.
The Northern Mariana Islands have a bicameral legislature, with 20 seats in the House and 9 in the Senate. They also have similar political parties, with the addition of the Covenant party which advocates governmental and financial reforms, but the Republican party currently dominates. There are more seats held by Republicans than Independents, and no seats held by Democrats in both the House and the Senate.
In American Samoa, elections are officially non-partisan. Technically, American Samoa is governed by the US Department of the Interior and heavily dependent on the federal government for financial aid.
The US Virgin Islands have political parties that we recognize on the mainland. The legislature is a unicameral body with 15 members, 13 of which are democrats and 2 are independents.
Then the Puerto Rican legislative assembly is bicameral, consisting of a House with 51 members and Senate with 27 members. The political parties, however, don’t closely resemble those of mainland America. National parties do not compete in local elections, and mainly only exist to coordinate the presidential primaries in the territory.. That said, the New Progressive Party encompasses officials across a wide ideological spectrum and holds a two-thirds majority of the seats in the legislature now.
Incorporating every territory as a state would not seriously affect the balance of power in Washington. There is no clear indication that incorporation of all territories as states would give any advantage to the Republican or Democrat party. New issues would likely be introduced, and the presidential candidate travel list would grow, but the political status quo would be unlikely to change.