The then PM Anton Rop and FM Dimitrij Rupel deposited the documents with the then US Secretary of State Colin Powell at the White House alongside six heads of government from Central and Eastern Europe - Estonia, Lithuania, Latvia, Bulgaria, Romania and Slovakia.

NATO membership was endorsed in Slovenia at a referendum in March 2003 with a clear 66% majority.

Ten years on, however, only 40% would vote in favour, a Politbarometer poll has recently shown.

Presently one of the main questions raised about NATO is military spending, as a significant portion of the public continues to question the sensibility of spending money on the military considering that Slovenia has been in recession almost uninterruptedly for five years.

However, the military budget has been a prime target of austerity measures. Slovenia's defence spending had gone from 1.5% of GDP in 2004 to 1.6% in 2010, but by 2012 the share dropped to 1.1%, well short of commitments by all NATO members to spend at least 2% of GDP on defence.

Analysts quizzed by the STA before the anniversary acknowledge that Slovenia has benefited from NATO membership, while they also agree that NATO benefited from Slovenia's accession.

However, Uroš Svete, chair of the defence studies department at the Ljubljana Faculty of Social Sciences, also says that Slovenia could have played a more active role beyond the Western Balkans, and his colleague Zlatko Šabič maintains that Slovenia should better exert the value it has for NATO.

Meanwhile, sociologist Gorazd Kovačič says that Slovenian elites had pushed for NATO membership a decade ago "as a supplement for foreign policy, which they are incapable of formulating".