But EU policymakers say that because Bulgaria and Romania are full members of the 27-nation bloc, the EU has few hard instruments at its disposal to compel its two newest and poorest entrants to raise their standards.
In the months before Bulgaria and Romania joined in January 2007, the EU found itself in a trap, in which it sensed they were not ready for membership, but could not delay their entry without reneging on earlier promises and damaging the EU's reputation.
The accession treaties of Bulgaria and Romania contain three clauses that provide a legal basis for possible action against them, but they apply only until the end of 2009.
The "economic safeguard clause" permits action if either state's entry into the single market has damaged European economic sectors. This clause is unlikely to be invoked because the problems are not primarily economic in nature.
Under the "internal market clause", some EU-funded projects could be halted if, for example, Sofia or Bucharest were deemed not to have complied with public procurement rules. Agricultural subsidies could also be cut or withheld.
These are powerful weapons, because Romania is due to receive Ђ32bn ($51bn, Ј26bn) and Bulgaria Ђ11bn in aid by 2013. But some EU officials regard the punishments as unsuitable, because agriculture and procurement are not at the heart of the corruption problems.
The "justice and home affairs clause" lets other states refuse to recognise Bulgarian and Romanian court decisions if they have little confidence in the two countries' judicial systems. In extreme circumstances, EU states could invoke Article 7 of the Treaty on European Union.
This suspends certain rights of a member state if it is judged to be in "serious and persistent breach" of EU principles of liberty, democracy, human rights and the rule of law.