London  - This summer's conflict between Russia and Georgia should lead to a "more considered analysis" of NATO enlargement to avoid eastward expansion becoming a "game of Russian roulette," a leading defence research institute warned Thursday.

The London-based International Institute for Strategic Studies (IISS) said the conflict had marked the "distinct end of the romantic phase of the post-Cold War order" and cast doubt on whether Georgia would be a "responsible member" of the NATO alliance.

"Georgia has weakened its case for NATO membership," the IISS said in its Strategic Survey 2008 published Thursday.

At the same time, the conflict had shown that Russia was "not yet the liberal democratic power some both in Russia and outside wished for," the IISS said.

On a practical level, there was a high risk that the momentum of NATO enlargement - in the case of both Georgia and Ukraine - would divide the West, said the IISS.

While the US was likely to argue for continuing the path towards eventual membership Europeans had a strong case to argue that it would be in NATO's strategic interest to pause its enlargement policy, said the report.

"Europe will want to invite the US to think strategically, not nostalgically, about the weight it wishes to attach to NATO enlargement in its regional policy."

IISS-director John Chipman said NATO enlargement policy should take into account the alliance's strategic interests and "not become a means to an end, not an institutional priority in and of itself."

"NATO must not transform its expansion policy into a game of Russian roulette," said Chipman. (dpa)