Signatures for the referendum - 40,000 are needed - will be collected by Institute 25 June, a patriotic outfit, and the Party of the Slovenian Nation, a small nationalist party.
Making his appeal before the request for the collection of signatures was formally filed Monday afternoon, Pahor recalled that Croatia's NATO accession protocol was confirmed with a two-thirds majority in the National Assembly.
That vote in itself came after "a big political snag that could have turned into a major foreign policy crisis", so it would be "a shame if this referendum partially annulled that success," he said.
In case a referendum does take place, Pahor said the government would do its best to convince the people that Croatia's membership of NATO is in Slovenia's interest and has no direct bearing on reservations related to Croatia's accession to the EU.
"We have justified reservations about Croatia's EU entry and we have been able to convince the international community thereof with arguments, but now Croatia will be able to argue that Slovenia is causing trouble. This is an adverse circumstance for us," he said.
Institute 25 June lodged the request for the collection of signatures after the Foreign Policy Committee watered down today the wording of the statement on Croatia's NATO accession that the opposition People's Party (SLS) had proposed.
The outfit now has 35 days to collect the signatures, but this means Slovenia would be unable to submit the ratification protocol by 23 March as agreed by members of the alliance and Croatia would be unable to formally join NATO at the early-April summit.
Yet Marjan Podobnik, the head of Institute 25 June, said today referendum activities would be halted if parliament confirms the original SLS-backed wording of the statement saying that Slovenia recognises no Croatian regulations that prejudge the border.
Commenting on the statement adopted by the Foreign Policy Committee, Pahor said it was very moderate and considerately worded. He said it represented the gist of a declaration on bilateral relations that a some parties have been trying for years to get through parliament.