Complex sentence: When Pearson retired in 1968, Marchand was seen as the likely and strongest Quebec candidate to replace him but hedeclined to run for the Liberal party leadership, claiming that his English was not good enough.
Split into simpler sentences: When Pearson retired in 1968, Marchand was seen as the likely and strongest Quebec candidate to replace him. He declined to run for the Liberal party leadership, claiming that his English was not good enough.