Many of the more impenetrable problems Cyprus, India and Pakistan, Western Sahara are hardy perennials, resisting change.

ECONOMIST: A bit of respect, please

"Sanctuaries" for ballistic missile submarines, keep-out zones, limits on sea-launched cruise missiles and bans on various types of tactical nuclear weapons have been hardy perennials of Soviet diplomacy.

CENTERFORSECURITYPOLICY: Naval Arms Control: An Idea Whose Time Must Never Come

Corruption and poverty emerge as hardy perennials of global debate.

BBC: Unemployment is world's fastest-rising fear - survey