The “solidarity clause”, known more formally as Article 222 of the Lisbon Treaty, regulates the use of police, secret service and military means in case of a crisis within the EU. The EU Commission and the EU High Representative for Foreign and Security Policy issued a proposal in December for the legal implementation of the clause. 
When the clause is implemented, Member States and EU institutions will be bound to assist one another in the case of a disaster (“any situation, which has or may have an adverse impact on people, the environment or property,” according to the Commission’s proposal) or terrorist attack, as defined in the 2002 Council Framework Decision on combating terrorism. The clause determines that engagement in the territory of another state shall only be allowed at the “request of its political authorities”.
Documents produced by the Council working groups dealing with the issue of whether a threshold for the activation of assistance should be laid down in writing show that a dispute has arisen between Member States. The “solidarity clause” will apply only after all the capacities of the affected country are exhausted. But how is this to be determined?
A declaration specifically attached to the Lisbon Treaty states that in cases of assistance the choice of means shall be left to the assisting Member States. During debates held in March, Austria and the Netherlands sought to put in place severe restrictions on the provision of assistance, while Greece and Italy were in favour of a wide scope of application.
The German delegation to the Council argued that no new bodies should be established following the implementation of Article 222. However, EU secret service structures might be reinforced: it may “come into question” to hand responsibility for a regular “integrated risk and threat evaluation at EU level” to the EU’s Intelligence Analysis Centre (INTCEN), which is part of the European External Action Service. INTCEN would then be competent not just for “terrorism” but also for “organized crime, disaster protection, health, climate change and environment.”
The definition of crisis given by the legislative proposal is wide: “a serious, unexpected and often dangerous situation, requiring timely action: a situation that may affect or threaten lives, environment, critical infrastructure or core societal functions, may be caused by a natural or man-made disaster or terrorist attacks.”
A European Parliament resolution adopted in November 2012 demanded that the solidarity clause also cover “politically motivated blockades” as well as “attacks in cyberspace, pandemics, or energy shortages,”  but so far this does not seem to have been taken into account by Member State representatives in the Council: political conflicts have not yet been mentioned. However, “any situation which has or may have an adverse impact on people, the environment or property” could be interpreted as including uprisings, blockades or sabotage.
This issue was raised by two members of the European Parliament in October last year. Sabine Lösing and Willy Meyer gave a dissenting opinion in a parliamentary report on the implementation of Article 222, arguing that it is unclear if “social unrest/strikes are also considered ‘man made disasters’.” 
Member States are also debating the territorial application of the “solidarity clause”: should it be applicable on land, on sea and in the air? Some governments demand that it be extended to ships and airplanes travelling in non-EU regions, while the Commission and consulates have suggested including “offshore oil and gas platforms”. While embassies and consulates are not mentioned, their inclusion can be assumed.
Furthermore, application of the clause is required “whether the crisis originates inside or outside the EU”. The German government even considers “preventative measures” conceivable, for example in the context of “defence against a terrorist threat.” 
Solidarity or militarisation? Proposed ‘solidarity clause’ legislation criticised for lack of clarity and “encouraging armament”, Statewatch News Online, February 2013
Statewatch Analysis: Secrecy reigns at the EU’s Intelligence Analysis Centre by Chris Jones (pdf)
Solidarity Clause – the way ahead? – Orientation debate on Art. 222 TFEU, Statewatch News Online, October 2011
 European Commission/High Representative, Joint proposal for a Council Decision on the arrangements for the implementation by the Union of the Solidarity Clause, 16 January 2013
 Council Decision of 5 March 2007 establishing a Civil Protection Financial Instrument
 European Parliament resolution of 22 November 2012 on the EU’s mutual defence and solidarity clauses: political and operational dimensions
 Report on the EU’s mutual defence and solidarity clauses: political and operational dimensions, 31 October 2012
 Antwort der Bundesregierung auf die Kleine Anfrage der Abgeordneten Andrej Hunko, Annete Groth, Ulla Jelpke, weiterer Abgeordneter und der Fraktion DIE LINKE, 8 March 2013
Image: The EU secret service networking (all rights reserved EEAS).