The need for Canada to populate the land with people loyal to them and to have them send western resources east.
Open primaries are where voters don't have to declare party affiliation.
Closed primaries are for affiliated party members.
The cotton gin made it easy for slaves to separate seeds out of the cotton. However, it it increased slave usage all over. It actually increased the use of slavery. The cotton gin just made one part of a slaves job quicker and easier.