Chamberlain certainly made mistakes, but the Munich agreement was in fact a peace treaty that made peace, at the cost of Czech defenses. Hitler went beyond the agreement and took over the rest of Czechoslovakia (except for bits handed to Poland and Hungary), but that wasnt Chamberlains fault.
Let me begin by saying that I agree with a number of other posters that these "news" stories about Neville Chamberlain and Munich are transparent attempts to defend the Obama Administration's recent mishandling of the Syria crisis.
That said, I too am going to offer something of a contrarian view for FR about the Munich Agreement itself. The agreement was a bad choice for Britain, but it was a bad choice among other bad options.
By 1938, both Britain and France had neglected defense preparations for about a decade, a de facto bilateral policy that left someone like Chamberlain in a very poor position to act in 1938. This policy and its effects were was simply facts at the time of Munich, and this policy was the fundamental mistake. Not only were both Britain and France underprepared for war against a continental power, but the doubt each country therefore had about the other's willingness to maintain a wartime alliance between the two was quite reasonable.
Remember that Britain was not faced with destruction in 1938. Nor was the German absorption of Czechoslavakia itself a strategic threat to Britain. Britain reckoned, accurately, that should war be necessary it could be prosecuted later than the spring of 1938 from a position that was no worse than at that time.
It should be noted, too, that the strategic worries Britain had in 1938 about a major war all came to pass, as things actually happened, and the British ability to avoid these outcomes by declaring war in 1938 is doubtful. The Japanese would eventually have tried to take advantage of British weakness in the far East had Britain begun a major European war in 1938, just as actually happened, and there is no reason to think that these counterfactual Japanese adventures would have been any less disastrous for Britain than the actual ones. Germany would not have abandoned its broader war plans, and it would not have accepted any settlement denying it strategic dominance in Europe without being defeated in war. Britain only suspected as much about German intentions in 1938, true. Britain did realize, though, that the ability of Britain and France to inflict defeat on Germany in 1938 was not notably greater than they could expect it to be in the near future, such as in 1939, when war actually began.
The real significance of Munich was to make vivid the one fact that Britain and France were struggling to avoid facing. Should it be necessary to go to war to curb German aggression the two countries were neither willing nor able to do so.
This deficiency persisted right up to the start of the war in 1939. By the time Britain began preparing for war in earnest, it was too late to make good a decade of neglect. Hence the disasters that ensued.
In this respect, Britain was hardly unique. France, the United States, and the Soviet Union all systematically underestimated the German and Japanese threats, all of them neglected their defense preparations despite ample warnings of strategic danger, and all of them suffered numerous catastrophes as a result. The Munich Agreement was just the last dramatic demonstration of the danger the (eventual) Allied powers had allowed themselves to drift into before war actually began. By itself, it did little to alter the strategic situation for any of the belligerent powers.
The popular discussion of Munich tends to emphasize a narrative of personal weakness on Chamberlain's part. That is unfortunate, as the more important lesson derives from Britain's strategic weakness that left Chamberlain without good options.