Question: What eastern European border was disputed between it's two nations after World War I, was re-established in 1990 as an identical version of its former self, changed only in the name of one of it's nations?

<P0-S0> "Back to the Pilot" is the fifth episode of the tenth season of the animated comedy series "Family Guy". <P0-S1>  It originally aired on Fox in the United States on November 13, 2011. <P0-S2>  In "Back to the Pilot", two of the show's main characters, baby genius Stewie and anthropomorphic dog Brian, both voiced by series creator Seth MacFarlane, use a time machine to travel back in time to the first episode of the series, "Death Has a Shadow". <P0-S3>  Trouble ensues however, when Brian tells his former self about the September 11 attacks, causing the present to be dramatically changed, and ultimately resulting in a second civil war. <P0-S4>  The two must then prevent themselves from going back to the past in the first place, but soon realize that it will be much more difficult than they had originally thought. <SEP> <P1-S0>  The territory was disputed between Poland and Lithuania after World War I. <P1-S1>  This dispute was the main cause of the brief Polish-Lithuanian War and the Sejny Uprising. <P1-S2>  The conflict was later overshadowed by a much larger and more serious Polish-Lithuanian dispute over the Vilnius Region. <P1-S3> Suwałki Region (Polish: "Suwalszczyzna" , Lithuanian: "Suvalkų kraštas, Suvalkija" ) is a small region around the city of Suwałki (known in Lithuanian as "Suvalkai") in northeastern Poland near the border with Lithuania. <P1-S4>  The Suwałki Region remains a major center of the Lithuanian minority in Poland. <SEP> <P2-S0> The current Lithuania–Poland border exists since the re-establishment of the independence of Lithuania on March 11, 1990. <P2-S1>  Until then the identical border was between Poland and Lithuanian SSR of the Soviet Union. <P2-S2>  The length of the border is 104 km . <P2-S3>  It runs from the Lithuania–Poland–Russia tripoint southeast to the Belarus–Lithuania–Poland tripoint. <SEP> <P3-S0> The foreign relations of Eritrea are the policies of the Eritrean government by which it administers its external relations with other nations. <P3-S1>  Since its independence, Eritrea's foreign relations have been dominated by conflict and confrontation, both in the regional and international arenas. <P3-S2>  It has maintained often troubled, and usually violent, relations with its neighbors, including brief armed conflicts with Yemen and Djibouti and a destructive war with its bigger-neighbour, Ethiopia. <P3-S3>  At present, Eritrea has very tense relations with neighboring Ethiopia and Djibouti. <P3-S4>  Relations in the international arena also have been strained since the last decade, particularly with major powers. <P3-S5>  What appeared cordial relations with the US in the 1990s turned acrimonious following the border with Ethiopia, 1998-2000. <P3-S6>  Although the two nations have a close working relationship regarding the ongoing war on terror, there has been a growing tension in other areas. <P3-S7>  Ties with international organizations such as the UN, African Union, and the EU have also been complicated in part because of Eritrea's outrage at their reluctance to force Ethiopia to accept a boundary commission ruling issued in 2002.