1989年後，隨著冷戰結束，歷史終結論甚囂塵上，論者多認為自由主義式民主已是人類終極最佳政府形式，更有論者預言威權體制終將崩潰，自由主義式民主被視為主流典範體制。然時序進入21世紀後的全球政治現實並未如預期。一方面全球民主出現12年持續衰退，另方面威權韌性則因展現治理實績而益加彰顯，再方面則是混合體制漸受青睞。於此情況，自由主義式民主似乎面臨了種種侷限。吾人要如何掌握這些侷限呢？本文以「理論與制度的內憂外患」為概念架構，對自由民主之種種侷限和挑戰進行體系性初步考察。分析結果顯示：當代自由主義式民主不僅在理論上有內部限制和外部挑戰，在制度上也有內在侷限和外部制約，其典範赤字已昭然若揭。那麼，自由民主之未來將如何？本文認為吾人應進一步深究自由民主各種侷限之根源，作為自由民主更新或體制調整之參考。

The argument that liberal democracy is the end of history has prevailed since the end of the Cold War in 1989. Many commentators announced that liberal democracy will be the final and the best form of human government. Moreover, some scholars predicted that those authoritarian regimes will inevitably collapse in years. Under these circumstances, liberal democracy seems to be recognized as the dominant paradigm regime. However, the global landscape demonstrated by the political reality from the beginning of the 21st century does not confirm that argument and prediction. On the one side, both advanced and emerging democracies have suffered from democratic recession in 12 consecutive years from 2006; on the other side, the authoritarian resilience has been proved by credible performance of state governance in core authoritarian states like China and Russia. What are the challenges and limits of liberal democracy? This article tries to make a nascent systematic analysis on these issues by offering a reflective conceptual framework focused on “troubles within and without, theoretical and institutional.” It finds that, on the one hand, three theoretical premises upon which liberal democracy embeds have suffered from respective defects; on the other hand, liberal democracy, while implemented by institutional arrangements, has its intrinsic and extrinsic limits in light of global practical experiences. Accordingly, because liberal democracy has suffered from paradigm deficits, it is hardly considered as the end of history. What is the future of liberal democracy?This article suggests that we might make efforts to delve into the real causes of its limits in order to find out the approaches for democratic revival or regime adjustment.