Бірінші дүниежүзілік соғыстан кейінгі «Теңіздер арасындағы» мемлекеттік жобасы

Proposed country during World War I

Intermarium (Międzymorze, ) was a post World War I geopolitical plan conceived by Józef Piłsudski to unite former Polish–Lithuanian Commonwealth lands within a single polity. The plan went through several iterations, some of which anticipated the inclusion of neighbouring states. The proposed multinational polity would have incorporated territories lying between the Baltic, Black, and Adriatic Seas, hence the name Intermarium (Latin for "Between Seas"). Prospectively a federation of Central and Eastern European countries, the post World War I Intermarium plan pursued by Piłsudski sought to recruit to the proposed federation the Baltic states (Lithuania, Latvia, Estonia), Finland, Belarus, Ukraine, Hungary, Romania, Yugoslavia, and Czechoslovakia. The Polish name Międzymorze (from między, "between"; and morze, "sea"), meaning "Between Seas", was rendered into Latin as Intermarium. The proposed federation was meant to emulate the Polish–Lithuanian Commonwealth, stretching from the Baltic Sea to the Black Sea, that, from the end of the 16th century to the end of the 18th, had united the Kingdom of Poland and the Grand Duchy of Lithuania. Intermarium complemented Piłsudski's other geopolitical vision, Prometheism, whose goal was the dismemberment of the Russian Empire and that Empire's divestment of its territorial acquisitions. Intermarium was perceived by some Lithuanians as a threat to their newly established independence, and by some Ukrainians as a threat to their aspirations for independence, and while France backed the proposal, it was opposed by the Soviet Union and by most other Western powers. solemnized by the marriage of Poland's Queen Jadwiga and Lithuania's Grand Duke Jogaila of the Gediminid dynasty, who became King Władysław II Jagiełło of Poland. A longer lasting federation subsequently came about in 1569 in the form of the Polish–Lithuanian Commonwealth, an arrangement that lasted until 1795, i. e., until the Third Partition of the Poland. The Polish–Lithuanian alliance thus lasted a total of 410 years, and constituted at times the largest state in Europe. Under the Commonwealth, proposals were advanced to establish expanded, Polish–Lithuanian Muscovite or Polish–Lithuanian–Ruthenian Commonwealths. Though the Commonwealth temporarily controlled parts of Russia and governed much of Ruthenia for centuries, these proposals were never implemented at a constitutional level.

Between the November and January Uprisings, in the period between 1832 and 1861, the idea of resurrecting an updated Polish–Lithuanian Commonwealth was advocated by Prince Adam Jerzy Czartoryski, residing in exile at the Hôtel Lambert in Paris. In his youth, Czartoryski had fought against Russia in the Polish–Russian War of 1792; he would have done so again in the Kościuszko Uprising of 1794 had he not been arrested at Brussels on his way back to Poland. Subsequently, in 1795, he and his younger brother had been commanded to enter the Imperial Russian Army, and Catherine the Great had been so favourably impressed with them that she had restored to them part of their confiscated estates. Adam Czartoryski subsequently served the Russian emperors Paul and Alexander I as a diplomat and foreign minister, establishing an anti French coalition during the Napoleonic Wars. Czartoryski, one of the leaders of the Polish November 1830 Uprising, had been sentenced to death after its suppression by Russia, but was eventually allowed to go into exile in France. In Paris the "visionary" statesman and former friend, confidant, and de facto foreign minister of Alexander I acted as the "uncrowned king and unacknowledged foreign minister" of a nonexistent Poland. In his book, Essai sur la diplomatie (Essay on Diplomacy), completed in 1827 but published only in 1830, Czartoryski observed that, "Having extended her sway south and west, and being by the nature of things unreachable from the east and north, Russia becomes a source of constant threat to Europe." He argued that Russia would have done better cultivating "friends rather than slaves". He also identified a future threat from Prussia and urged the incorporation of East Prussia into a resurrected Poland. Czartoryski's diplomatic efforts anticipated Piłsudski's Prometheist project in linking efforts for Polish independence with similar movements of other subjugated nations in Europe, as far east as the Caucasus Mountains, most notably in Georgia. Czartoryski aspired above all to reconstitute—with French, British, and Ottoman support—a sort of "pan Slavic" Polish–Lithuanian Commonwealth federated with the Czechs, Slovaks, Hungarians, Romanians, and all the South Slavs of the future Yugoslavia. Poland, in his concept, could have mediated the conflicts between Hungary and the Slavs, and between Hungary and Romania. The plan seemed achievable during the period of national revolutions in 1848–49 but foundered on lack of western support, on Hungarian intransigence toward the Czechs, Slovaks, and Romanians, and on the rise of German nationalism. Marian Kamil Dziewanowski writes that "the Prince's endeavour constitutes a [vital] link [between] the 16th century Jagiellon [federative prototype] and Józef Piłsudski's federative Prometheist program [that was to follow after World War I]." (The latter was his Prometheist project. According to Dziewanowski, the plan was never expressed in systematic fashion but instead relied on Piłsudski's pragmatic instincts. According to British scholar George Sanford, about the time of the Polish–Soviet War of 1920 Piłsudski recognised that the plan was not feasible.

Piłsudski's plan faced opposition from virtually all quarters. The Soviets, whose sphere of influence was directly threatened, worked to thwart the Intermarium agenda. The Lithuanians, who had re established their independence in 1918, were unwilling to join; the Ukrainians, similarly seeking independence, likewise feared that Poland might again subjugate them; argued for an ethnically homogeneous Poland in which minorities would be Polonised. Many Polish politicians, including Dmowski, opposed the idea of a multiethnic federation, preferring instead to work for a unitary Polish nation state. others view such claims with skepticism, pointing out a coup d'état in 1926 when Piłsudski assumed nearly dictatorial powers. In particular, his project is viewed unfavourably by most Ukrainian historians, with Oleksandr Derhachov arguing that the federation would have created a greater Poland in which the interests of non Poles, especially Ukrainians, would have received short shrift. Some historians hold that Piłsudski, who argued that "There can be no independent Poland without an independent Ukraine", may have been more interested in splitting Ukraine from Russia than in assuring Ukrainians' welfare. He did not hesitate to use military force to expand Poland's borders to Galicia and Volhynia, crushing a Ukrainian attempt at self determination in disputed territories east of the Bug River which contained a substantial Polish presence (a Polish majority mainly in cities such as Lwów, surrounded by a rural Ukrainian majority). Speaking of Poland's future frontiers, Piłsudski said: "All that we can gain in the west depends on the Entente—on the extent to which it may wish to squeeze Germany", while in the east "there are doors that open and close, and it depends on who forces them open and how far". In the eastern chaos, the Polish forces set out to expand as far as feasible. On the other hand, Poland had no interest in joining the western intervention in the Russian Civil War

In the aftermath of the Polish–Soviet War (1919–1921), and the establishment of the Ukrainian SSR, Piłsudski's concept of a federation of Central and Eastern European countries, based on a Polish Ukrainian axis, lost any chance of realisation. Piłsudski next contemplated a federation or alliance with the Baltic and Balkan states. This plan envisioned a Central European union including Poland, Czechoslovakia, Hungary, Scandinavia, the Baltic states, Italy, Romania, Bulgaria, Yugoslavia, and Greece—thus stretching not only west east from the Baltic to the Black Sea, but north south from the Arctic Ocean to the Mediterranean Sea. In comparison, Czechoslovakia had more success with its Little Entente (1920–1938) with Romania and Yugoslavia, supported by France. Piłsudski died in 1935. A later, much reduced version of his concept was attempted by interwar Polish Foreign Minister Józef Beck, a protégé of Piłsudski. His proposal, during the late 1930s, of a "Third Europe"—an alliance of Poland, Romania, and Hungary—gained little ground before World War II supervened. For economic reasons, there was a tendency in eastern Europe to follow the lead of Berlin rather than Warsaw. According to some historians, it was the failure to create a strong counterweight to Germany and the Soviet Union, as proposed by Piłsudski, that doomed Intermarium's prospective member countries to their fates in World War II.

The concept of a "Central [and Eastern] European Union"—a triangular geopolitical entity anchored in the Baltic, Black, and Adriatic or Aegean Seas—was revived during World War II in Władysław Sikorski's Polish Government in Exile. A first step toward its implementation—1942 discussions among the Greek, Yugoslav, Polish, and Czechoslovak governments in exile regarding prospective Greek–Yugoslav and Polish–Czechoslovak federations—ultimately foundered on Soviet opposition, which led to Czech hesitation and Allied indifference or hostility. On 12 May 2011, the Visegrád Group countries (The Republic of Poland, the Czech Republic, the Slovak Republic, and Hungary) announced the formation of a Visegrád Battlegroup under Polish command. The battlegroup was in place by 2016 as an independent force, not part of the NATO command. In addition, starting in 2013, the four countries were to begin joint military exercises under the auspices of the NATO Response Force. Some scholars saw this as a first step toward close Central European regional cooperation. On 6 August 2015, Polish President Andrzej Duda, in his inaugural address, announced plans to build a regional alliance of Central European states, modeled on the Intermarium concept. In 2016 the Three Seas Initiative held an initial summit meeting in Dubrovnik, Croatia. The Three Seas Initiative has 12 member states along a north–south axis from the Baltic Sea to the Adriatic Sea and the Black Sea: Estonia, Latvia, Lithuania, Poland, Czechia, Slovakia, Austria, Hungary, Slovenia, Croatia, Romania, and Bulgaria.