Decades ago, when right-to-die movement first got underway, the Swiss gave broad support to a practice widely viewed as a personal choice. Backed by the world's most liberal right-to-die laws, assisted-suicide groups have since then quietly helped thousands kill themselves. Lately, the increasingly controversial activities of Dignitas and its founder, Ludwig Minelli, are pushing even the famously tolerant Swiss too far, prompting calls for changes in the nation's assisted-suicide law. Mr. Minelli has long played the agent provocateur of Switzerland's right-to-die movement, most notably because his group helps the lion's share of foreigners who come to Switzerland seeking to end their lives.