After the Croatian parliament ratified the North Atlantic Treaty on 25 March this year and forwarded the ratified document to Washington, following an invitation from the alliance's Secretary-General, Croatia became a full member of NATO and will attend the forthcoming summit on the occasion of the alliance's 60th anniversary in Strasbourg and Kehl in as a full member.
On 7 April, flags of the two newcomers Croatia and Austria will be hoisted in fromnt of the NATO headquarters in Brussels, and Croatia will on the same day raise NATO's flag in front of the main offices of its defence ministry.
At the NATO summit in Bucharest in April 2008, Croatia and Albania were invited to join the alliance.
After that, two rounds of negotiations on their admission ensued, wrapping up on 7 May 2008.
It was agreed at the negotiations that Croatia would pay between three and four million euros into the alliance's joint budget, which is one of the lowest monetary contributions of member-states.
Upon the completion of those negotiations, Croatia sent a letter of intent to NATO with a defined time-table for the completion of necessary reforms, which was the final step before the signing of an accession protocol by NATO's 26 countries on 9 July 2008.
The signing paved the way for the ratification of accession protocols for Croatia and Albania in parliaments of the member states.
This part of the procedure went smoothly except in Slovenia, where a nonparliamentary party tried to procrastinate the process for Croatia after the national parliament ratified the document on 9 February 2009.
The nonparliamentary SSN wanted to organise a referendum contesting the ratification of Croatia's accession protocol, which would have delayed Slovenia's deposition of the ratified document, but did not manage to collect the required number of signatures for the referendum.
On 9 April 1949, 12 countries: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom and the United States, signed the North Atlantic Treaty at the Departmental Auditorium in Washington D.C., which was the founding document of the North Atlantic Treaty Organisation (NATO).
They were bound to defend themselves against the risks of the impact of Soviet Union expansion from East Europe to the rest of the continent.
With the end of the Cold War, NATO carried out its primary role, and since then it has adjusted to new security challenges such as international terrorism, mass destruction arms proliferation, the security of energy sources, and natural disasters.
According to the Treaty's Article 5, "the Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area".
The sixth wave of the alliance's enlargement, that is the admission of Croatia and Albania, has brought the total number of members to 28.
Croatia defined its NATO membership as one of its foreign policy priorities in the mid- 1990s.
The first step on this road was taken in 1996 when Croatia applied for joining the Partnership for Peace Programme, which the alliance launched for aspirants in 1994.
Croatia was allowed to join PfP on 25 May 2000 in Florence, when Zagreb signed a framework document of PfP and Croatia was officially granted PfP member status.
On 15 May 2002, Croatia was invited to take part in the Membership Action Plan-MAP at an AECP (Euro-Atlantic Partnership Council) meeting in Reykjavik.
Within its preparations for NATO membership, Croatia adopted a long-term plan for the development of its armed forces from 2006 to 2015.
The plan envisages that the armed forces would include no more than 16,000 active military staff, 2,000 civilian staff, 2,000 voluntary conscripts per year, plus 6,000 in reserve.
As of 2010, only professionals will be used and the emphasis is on creating professional, mobile, deployable and financially viable forces that are interoperable with NATO forces.
Furthermore, eight percent of the land forces will be deployed and ready for deployment in international military operations, and 40 percent will be trained to participate in operations outside Croatia. This figure includes some 4,100 active military staff who will be equipped and trained for rotation in NATO, UN and EU missions.
Of that number, 700 troops will permanently participate in UN and NATO missions as of 2011.
In the long term, up to 1,600 troops will rotate in the NATO Response Force and the EU combat force. Croatia will train units that are ready to participate in NATO actions at any moment.
A reinforced motorized infantry battalion is expected to be organised and equipped by 2012.
By 2015, Croatia will outfit nine facilities for NATO requirements involving transit, exercises, assembly and emergencies. The facilities include barracks in Gasinci, Benkovac, Delnice and Vinkovci, airports in Pula, Zagreb and Zadar, and the naval port Lora in Split. These will not be NATO bases but will be used by the Croatian army.