Before WWII, is there a connection between Protestantism and the success of Capitalis

Idly pondering successful market economies, prior to the emergence of Japan, it occurred to me that the common trait among successful nations was a Protestant majority. Majority Catholic countries seem to have struggled or failed with free market systems. Is this a valid conclusion? Is there anything published on the matter?

It's an invalid conclusion in that it discounts any success before the failures. Spain, France, Italy and G. Britain were all world powers at a point in time.

France would be the main exception. In reality it depends on how long before World War Two you're talking about. The western world was in depression pretty much from 1929 until 1939, if you want to go back centuries then yes, actually, most of the successful prosperous capitalist countries were areas with Protestant majorities, from the Golden Age of the Netherlands through to Germany's prosperity and the early rule of the Nazis.

There is a degree of co-relation, albeit convoluted, between Protestantism and capitalism. As an argument it is easy to fault but it was believed for a long time. One of the main traits of, particularly Presbyterianism for a while was the notion of predestination. Seeing as the puritanical movement, which can be described without too much controversy as heavily influenced by Presbyterianism was characterized largely by its insistence that God's word was visible and obvious, it merged worth with value. It goes like this.

God favors the virtuous (or at least the faithful, though the distinction was invisible to the adherents at the time).
God rewards those he favors.
God's wish is at all times visible in the world (this is taken extremely literally)
Therefore the wealthiest must be the most admired by God.
Therefore capitalism is God's will as his power will allow the virtuous to become wealthy.

It is an extremely dated argument, but was common in parts of Protestant Europe and America until the Nineteenth Cenutry. Now, I'm not going into the flaws of the argument, they are obvious and even if you accept it, there are obvious contradictions within. But there was a time when it was assumed by several people, mostly of Presbyterian background, that predestination meant not just that the virtuous would be rewarded in the next life, but that they are rewarded in this one through material wealth. This was never a mainstream view, and certainly the rich used it to justify their wealth.

The reality is also reversible. Protestantism became popular in those areas of Europe that were already prosperous. The educated middle classes that emerged in Europe during the Renaissance were mostly hostile to Rome's power, but within Italy had no power to do anything but moan. When the printing press allowed the Bible to be mass circulated to a population with decent levels of literacy for the first time, this was in Germany, Switzerland, Netherlands, France, readers found contradictions between the text and official church doctrine, which became the backbone of the Reformation. In France the monarchy was powerful enough to enforce Catholicism, in the rest of Europe it took hold, because the small, local leaders of city-states had to keep the local middle classes onside, and ending tithes played a big part. England later became Protestant entirely due to Henry VIII's self-interest (which is not to belittle the genuine belief of millions of Europeans, but the leaders of the day were extremely cynical when deciding which religion to back).

So there is a link between Capitalist success, going way back to the 1600's, and Protestantism, and also a link, in some quarters between forms of protestantism and support for Capitalism. but with Japan as your obvious counter-example, it is by no means a clear cut thing.

No; you have to remember that there were other factors, such as race, involved in the success of capitalists. For example, Spain is a Catholic country. But the fact that the Spanish would rather lie on a beach than start a business and become wealthy has nothing to do with the fact that they are Catholic. Besides, France, a Catholic country, was at one time the wealthiest country in Europe. As well, England was a very successful country long before Anglicanism appeared. Austria! The Austrians are huge Catholics, and they are a highly wealthy country (Glock is based in Austria, by the way).

Luther released the sin of Usury which kept Capitalism underdeveloped for eons, however Capitalism was a system in use. The main impetus for Capitalism was the trade of the Italian city States, mainly Venice.

The first post Luther Capitalistic venture in N. Europe was the Tulip trade which you can look on on the Internet.

There are books on this subject:

Max Weber THE PROTESTANT ETHIC AND THE SPIRIT OF CAPITALISM

Ernst Troelsch - PROTESTANTISM AND PROGRESS

R. H. Tawney - Religion & the Rise of Capitalism

were the first and the most important. There were others, of course, that made the connection between the rise of Protestantism and the rise of Capitalism.