The January 2007 Sydney conference that Hizb ut-Tahrir (HT, the Party of Liberation) organised raises dilemmas that have a long history in liberal democracies. HT encourages indirectly, and sometimes more directly, political violence by its inciting propaganda. It uses Australian tolerance to promote radical propaganda, even against Australia itself. This paper argues that HT’s proselytising remains to date on the acceptable side of anti-terrorism and sedition legislation. A ban on HT is not yet justified. But this group warrants intensive monitoring.