Britain's Home Secretary Theresa May has vowed to introduce new laws banning extremist groups and radical Islamist preachers even if they have not been convicted of any specific criminal offence.
Dismissing criticism from civil liberties activists that such steps amount to punishment without due legal process, Mrs May told the annual conference of the Conservative Party this week that Britain needed to be defended from extremists who otherwise "stay just within the law" but still seek to undermine public order, adding that "we must stand up to our values".
The "Extremism Disruption Orders" will be implemented if the government retains power at next year's general election. But many other Western countries have either introduced or are considering similar laws.
Britain is a trailblazer in this area partly because the country has been subjected to various terrorist threats for more than half a century, but also because, in the absence of a written Constitution or criminal code, judges frequently challenge government powers.
Under recent measures, the government may not only cancel the passport of anyone suspected of volunteering for terrorism, but can also annul the citizenship of anyone who took up British nationality and then engaged in hostile activities.
Evidence against suspected terrorists can now be heard by judges in secret, to protect intelligence sources.
The protection of spying activities is also the subject of legislation approved yesterday in Australia: It threatens anyone compromising an intelligence operation or disclosing its details with up to 10 years in jail.
And this is just the first step in a package of new measures which Australia plans to introduce; others include the creation of a new criminal offence of travelling to any area of the world which the Australian authorities declare off-limits, a novel approach which, if it works, is likely to be copied by other countries.
France, too, has introduced tough regulations to stem terrorist recruitment among Europe's single-biggest Muslim community.
Paris now has the powers to refuse issuing a passport to anyone it suspects of volunteering for terrorism, as well as shutting down any website it believes to be promoting violence.
Early next week, the French Senate is scheduled to approve a new law which will extend the offence of planning for a "terrorist conspiracy" to single individuals; until now, only two people or more could technically be accused of a conspiracy.
"The loophole has to be closed, for there is a growing tendency for would-be jihadis to operate on their own," explains Mr Gilles de Kerchove, who is responsible for counter-terrorism coordination in the European Union.
The Germans, who were stunned to discover that at least 400 of their citizens may now be fighting in Syria and Iraq, are also seeking to tighten their anti-terrorism laws.
Mrs Eva Hogl, an MP from the centre- left Social Democrats who share power with Chancellor Angela Merkel's conservatives, this week said the ruling coalition in Berlin had "agreed on a series of steps in order to better address the Islamist threat".
But Germany's turbulent history is proving to be a hindrance. Because the Nazi dictatorship arbitrarily deprived German Jews of their nationality during the 1930s, the introduction of new regulations withdrawing German citizenship from would-be terrorists is a "delicate matter", a spokesman for the Interior Ministry admitted.
Equally difficult is the imposition of restrictions on the right of Germans to travel abroad, or the granting of wider powers to the intelligence services to collect and store private data.
Absent from all these legal efforts, however, are any new ideas on how to prevent the phenomenon of radicalisation in the first place.
Previous schemes launched with great fanfare and plenty of cash in Britain and France are acknowledged to have failed and, in the absence of anything better, European politicians are steering clear of such ideas.