The effect of telling this story in chronological order is It helps the reader understand how the UMWA affected labor movements through history.
Chronological structuring refers to the works with the timeline. In the above passage it provides the history of the UMWA, on how it influenced the political parties in 1901 and later in 1903, how they asserted their power and in 1908, company's owner voted to cut down wages.
The sequence is chronological in accordance with a timeline which moves the story effectively and shows how thing moved over time. It helps in solving the riddles by getting together the facts.
