Hungary’s power-hungry Prime Minister, Viktor Orban, appears to think he can call Europe’s bluff. Brussels must make it clear that he cannot. And it must do so swiftly.

The Hungarian parliament will vote today on constitutional amendments curbing press freedom and threatening the independence of both the judiciary and the Church. If passed, coverage of election campaigns will be restricted to state media only, and all decisions made by the country’s highest court before 2012 will be invalid. Extra rules on everything from higher education to homelessness to family law are also included.

The implications for Hungary’s democratic checks and balances are grave. Nor is this Mr Orban’s first attempt at an alarming consolidation of government power. He has already tried to push through such changes once, but was forced by international pressure to back down. Now, however, the proposals have resurfaced as a series of amendments put forward by Mr Orban’s Fidesz party, which dominates parliament.

There is no shortage of opposition second time around, either. Several thousand people marched through Budapest on Saturday. Both the Council of Europe and the US have expressed disquiet. And José Manuel Barroso, the President of the European Commission, last week explicitly warned that the changes put the rule of law of risk, and requested such concerns be addressed. Mr Orban’s reply was non-committal, however, affirming a commitment to EU law but giving no details.

Europe has more than the power of persuasion to draw on, though. There is the possibility of imposing financial penalties on Hungary, restricting the several billion euros-worth of annual structural funds. There is also the nuclear option of withdrawing the country’s EU voting rights.

Both are blunt instruments. Neither is a course to be taken lightly. But Mr Orban’s agenda – cloaked in private bills from Fidesz MPs, or not – is no trifling matter. It runs counter to the most fundamental of Europe’s democratic values. It is up to Brussels to defend the integrity of those values and to show Budapest that membership of the EU comes with responsibilities that cannot simply be shrugged off.