LTVilniaus klausimas Steigiamajame Seime buvo svarstomas ne viename posėdyje. Tai buvo bene svarbiausia problema per visą tarpukario laikotarpį. Yra nemažai tyrimų apie tai, tačiau atskirai netyrinėti Steigiamojo Seimo nutarimai ar sprendimai, siekiant prijungti ir išlaikyti Vilniaus kraštą. Šio pranešimo tikslas - parodyti ir išanalizuoti Steigiamojo Seimo, jo frakcijų ir kai kurių atstovų požiūrį Vilniaus klausimu 1920 m. Šaltiniai leidžia Steigiamojo Seimo vaidmenį, sprendžiant Vilniaus problemą, nagrinėti trimis aspektais: 1. Diskusijos ir svarstymai Seimo posėdžiuose; 2. Vienos iš koalicijos frakcijų - valstiečių liaudininkų posėdžių nutarimai; 3. Seimo delegacijų veikla. Tyrimui pasirinktas chronologinis principas, nes taip galima aiškiau atskleisti Seimo politinių sprendimų raidą. Tyrimo chronologinės ribos - 1920 m. gegužės 15 d.-1920 m. gruodžio pabaiga. [p. 33].
ENThe Constituent Seimas put efforts to get Vilnius back during the Polish-Bolshevik war. The opposition of the Polish armed forces prevented the Lithuanian armed forces from entering into Vilnius be fore the Red Army. The Seimas wanted to make the Bolsheviks leave Vilnius as soon as possible according to the Moscow treaty. Its members saw threat in the Bolshevik actions of establishing revolutionary committees, and it demanded the Government to take measures. The ruling majority in the Seimas did not want plebiscite in the Vilnius territory because they did not believe that the results of it would be favorable to Lithuania. Only social democrats wanted to give the right of self-determination to residents of the Vilnius territory. In the negotiations in Kalvarija and Suwałki, the Lithuanian del egation, including a member of the Seimas, V. V. Čarneckis, aimed at protecting the Vilnius territory from the Polish invasion. When the Polish armed forces started their attacks, almost all fractions of the Seimas supported the defense of the State, except for the Polish fraction, which did not express its loyalty to Lithuania. The Constituent Seimas took all measures to rally people for the defense of Lithuania: it established the Chief Defense Committee of Lithuania, which organized propaganda and collection of funds for the armed forces. In order to hold Vilnius and to defend the country against Poles, the Constituent Seimas sent delegations to the League of Nations and the Entente countries. When the L. Zheligovsky troops occupied the Vilnius territory, delegations of the Seimas went for support to Latvia, and then to Warsaw for negotiations with Poles. Unfortunately, all negotiations with Poles were vain.