At the request of Liechtenstein's government in 1919, Switzerland safeguards Liechtenstein's interests and citizens abroad. The two form a common economic and monetary area (Liechtenstein uses the Swiss franc (since 1920) and has a customs union (since 1924) with Switzerland) with open borders (though both are now also party to the Schengen Agreement): an entry visa for Switzerland applies to Liechtenstein. The countries also have a common patent system. Switzerland is empowered to enter into treaties on Liechtenstein's behalf if Liechtenstein is not represented at the treaty negotiations; this power has most often been exercised with treaties involving customs duties or procedures.
Swiss consular protection is extended to citizens of Liechtenstein and Switzerland represents Liechtenstein abroad unless they choose otherwise. Before Liechtenstein became a member in its own right of the European Free Trade Association, Switzerland represented its interests in that organization.
The two also share a common language (German) and are both outside the European Union. Liechtenstein relies on Switzerland for its national defence as it has no army of its own. Like its neighbour, it maintains a policy of neutrality. Ambassadors to one country are usually accredited to both (the only one resident in the country is from the Sovereign Military Order of Malta).
Incidents involving the Swiss military
- On 5 December 1985, rockets fired by the Swiss Army landed in Liechtenstein, causing a forest fire. Compensation was paid.
- On 13 October 1992, following written orders, Swiss Army cadets unknowingly crossed the border and went to Triesenberg to set up an observation post. Swiss commanders had overlooked the fact that Triesenberg was not on Swiss territory. Switzerland apologized to Liechtenstein for the incident.
- In March 2007, a company of 171 Swiss soldiers mistakenly entered Liechtenstein, after taking a wrong turn in the darkness. The troops returned to Swiss territory before they had travelled more than 2 km into the country. The Liechtenstein authorities did not discover the "invaders", and were informed by the Swiss after the incident. The incident was disregarded by both sides. A Liechtenstein spokesman said "It's not like they invaded with attack helicopters".
- Principality of Liechtenstein, Swiss Federal Department of Foreign Affairs
- "Switzerland and Liechtenstein: December 2000". World Trade Organization. 2000-12-06. Retrieved 2012-09-16.
- "Switzerland Invades Neighbor". Swiss French Television. 2007-03-05. Retrieved 2009-11-28.[unreliable source?]
- "Swiss Inform Liechtenstein of Error in Troop Maneuvers". New York Times. 1992-10-18. Retrieved 2009-11-27.
- "Swiss in Liechtenstein 'invasion'". BBC News. 2007-03-03. Retrieved 2007-03-03.
- (French) http://www.courrierinternational.com/article.asp?obj_id=71448