MP Rolandas Pavilionis has sparked heated debate by pushing for a referendum on whether Lithuania should join NATO - in defiance of the New Union party of which he is a member.
The controversial ex-rector of Vilnius University told reporters he planned to collect enough signatures from MPs to force a referendum.
"I don't think the NATO issue can be decided merely by resolutions," he told the Baltic News Service.
"First of all we have to ask the nation, and I invite members of Parliament to support the idea of holding a referendum."
With the approach of the holiday season it would become increasingly difficult to gather enough signatures from the public, the other way of forcing a referendum, Pavilionis said later on Lithuanian radio.
The response from MPs and officials has been to pour cold water on the idea.
Parliamentary chairman and New Union leader Arturas Paulauskas called the proposal unnecessary, saying all parliamentary parties had already agreed on the issue of NATO membership.
In a written statement the New Union, the junior party in the governing coalition, said voters had mandated the party to carry out its election pledges, which included seeking NATO membership.
The statement also cited a Foreign Ministry recommendation that important foreign policy issues should not be used for political gain.
This was echoed by Gediminas Kirkilas, spokesman for the Social Democratic Party, the senior party in the governing coalition.
Such arguments appear to contradict the constitution, which was itself adopted by a 1992 referendum and states that all important matters in the life of the nation are to be subject to public referendums.
Earlier this year President Valdas Adamkus stressed the necessity for referendums in such circumstances, with reference to European Union accession.
Although a NATO referendum stands little chance of becoming reality the idea has sparked debate on the meaning of democracy, with Pavilionis appearing on a TV talkshow to argue his case with a panel of officials.
"Will we suddenly disappear if NATO doesn't take us in?" Pavilionis asked rhetorically.
Pavilionis is well known for his vociferous attacks on NATO's bombing in Yugoslavia during the Kosovo conflict, and for flouting a police blockade during last year's NATO Parliamentary Assembly session which prevented him from reaching his Vilnius University office.