The EU "must be able to react swiftly and effectively to ensure compliance" with the bloc's basic principles if a member country is seen as backsliding, including a last-resort option to cut EU funding to offenders, the foreign ministers of Germany, the Netherlands, Finland and Denmark said.
The European Union is able to fine companies like Redmond, Washington-based Microsoft Corp. if they are caught breaching its antitrust rules, but the 27-nation bloc is largely powerless if one of its member states changes its laws to curb the rule of law or democracy itself.
The ministers said in a joint letter to European Commission President Jose Manuel Barroso, obtained by The Associated Press on Friday, that the bloc must be "extremely watchful" whenever its fundamental values are put at risk.
The letter didn't name any countries, but EU officials in the past have expressed concern about legal changes or lax enforcement, especially in Romania, Bulgaria and Hungary.
The mechanism should allow the European Commission, the bloc's executive arm, to intervene in an early stage and require the country to remedy the relevant law or situation, provided the step is also backed by a majority of EU states, the ministers said in their letter dated Thursday.
Creating such a mechanism would likely require unanimity among the member states—including those identified as causing concern and from others such as Britain, which are opposed to ceding more power to Brussels.
Compliance with the EU's fundamental values was no problem when the bloc was essentially a club of mature Western European democracies, but the issue has come to the forefront since the enlargement in recent years to include 10 Eastern European post-Communist nations.
"We believe that once in place it could help secure public support for further enlargement," the ministers said, referring to ongoing negotiations on possible EU accession talks with several Balkan nations and Turkey.
European Commission spokeswoman Pia Ahrenkilde Hansen welcomed the letter as a "very interesting contribution," noting that Barroso had in the past called for a similar initiative.
Hungary, where a right-wing government with a majority large enough to change the country's constitution took power in 2010, has attracted attention several times, notably for laws seen as jeopardizing the independence of the central bank and judiciary, as well as the enactment of media laws that critics saw as curbing freedom of speech. On both accounts, EU officials and nations intervened and achieved some changes.
The EU, the U.S. State Department and the Council of Europe have all expressed concerns this week about a fourth round of amendments to Hungary's constitution that the government-party lawmakers are expected to approve Monday.
The changes are seen further eroding the democratic system of checks and balance by, for example, diminishing the powers of the Constitutional Court and adding to the constitution several laws which the court had struck down earlier as unconstitutional.
AP writer Pablo Gorondi in Budapest, Hungary, contributed reporting.
Juergen Baetz can be reached on Twitter at http://www.twitter.com/jbaetz