The Terran Empire, following the War of Unification, 2151-53 CE. Emperor Kresek I is declared Ruler of Mankind.
Jealous of those rebellious Jeffersonians who just would not get down on their bellies and grovel like proper subjects, his son Kresek II decides to gobble up the Republic...
Humanity's homeworld was badly damaged and heavily depopulated in the Imperial Unification and the Republic-Empire War which followed. The greatest scientific minds in the Republic and the former Empire have descended upon their wounded grandmother to coax her back to health. It will be a long and painful process, requiring generations of patient work. Traps left by the Empire, nuclear, chemical, and even biological, continue to take lives and damage the environment indiscriminately years after the cessation of hostilities.
In a very controversial decision, Old Texas, the former American state, has been granted independence as the Republic of Texas. That nation has existed previously: first between April and August, 1813 CE, deposed by Spanish royalist forces under Jose Alvarez de Toledo; again between 2 March 1836 and 29 December 1846 CE, with independence declared during the First Siege of the Alamo and confirmed at the Battle of San Jacinto, ending with the Republic being annexed by the United States after the Mexican-American War; and a third time between May and June, 2012 CE, in a standoff with United States Federal troops that ended with the deaths of forty-eight Texans after the Second Siege of the Alamo shortly before the fascist coup in the United States and the loss of American sovereignty to the United Nations.
The decision to grant sovereignty to the Fourth Republic of Texas has caused some apprehension in the Jeffersonian Republic. There are fears that New Texas, a valued and charter Member World, may seek its own independence. Some New Texans have left that world to take up residence in Old Texas, but thus far at least as many Old Texans have traveled to New Texas to begin earning Jeffersonian Citizenship.
The Fourth Republic of Texas does not suffer any restrictions on the building or arming of ships. Old Texas does have the nucleus of a space force, consisting of five "frigates" and various smaller craft liberated from the Imperial base at Corpus Christi, but obviously these are no serious threat or deterrent to any other nation. The decision to not restrict Old Texas' military is a source of potential hostility from the Russian Star Empire and the Kingdom of Nowy Kraków, who do suffer such restrictions under their treaties with the Republic.
Texas already has a significant source of revenue, at least, something each of its ancestor nations lacked; the former Imperial base at Corpus Christi is already in use as a civilian spaceport and is enjoying a great deal of business while Miami Spaceport's war damage is being repaired. The former Imperial repair facility at Galveston is being converted to construction, and Texas is expected to begin production of their equivalent of the Jeffersonian Republic's Tommy Atkins class general-purpose starships soon.
The remainder of the United States of America, and most other former Terran nations, have been absorbed by the Jeffersonian Republic. The sovereignty of Switzerland and Israel have been officially restored - at Geneva and Jerusalem, at least - but those nations are still in ruins from the War of Unification, and may never again be much more than city-states like the Vatican or the pre-Unification District of Columbia. Old Scotland, of course, is now an extension of the Republic of Caledonia. Most other nations have been so completely subjugated, first by the United Nations and then by the Terran Empire, that there is no significant national identity remaining.
Many former Israeli citizens are emigrating to New Israel, while the shattered remnants of the Swiss people continue to trickle into the Republic, and in both cases most have already begun the Citizenship process. Switzerland in particular was practically bombed off the map by Imperial warships during the Unification, after three conventional invasions, each larger than the last, were repelled with horrific Imperial losses. Israel's resistance was no less heroic, and her defeat by the Empire no less difficult or costly.