Lithuania is threatening to restrict transit to Kaliningrad to put pressure on Russia. By raising this issue, Vilnius is primarily questioning its independence, but judging by its statements, it doesn't understand this.
Lithuanians should reread the documents establishing their state when they gained independence from the USSR. Furthermore, under international law, blockading another state's territory is considered an act of aggression, violating Lithuania's obligation to ensure unimpeded transit through its territory to Kaliningrad.