> It absolutely produces different outcomes than a two party system. Smaller parties make demands as a condition for joining any coalition (or similar arrangement). For example, Canada's NDP only agreed to back the Liberal Government on condition of state funded dental care for children being implemented. Now it is. Millions are affected. Whether you agree with it or not - that is unquestionably a "meaningfully different outcome". Other examples abound if you care to look.
You think logrolling doesn't happen in the American system? Parties are made up of factions who will entertain each other's preferred priorities, which is the exact same thing you're describing except that the parties of the various factions are nominally the same. There's no real natural or obvious philosophical reason why your position on gun ownership should imply a position on environmental regulation, religion, infrastructure buildings, racial politics, abortion, tax policy, and more. We're so used to the groupings that they seem natural but if we go back and looking at older American party systems you'll see parties that don't 100% map onto the contemporary ones, with a blend of some elements we would think of as fitting and others we wouldn't.
It's unquestionably a different dynamic. If the party is in power, then the party is in power. Period. They have less incentive to listen to smaller factions. Do they? I sure hope so. But it's not the same.
Furthermore, these internal deals are more likely to be kept private since theres no benefit to airing everything to the press, the public and the opposition.
In a multi-party system almost all those deals are public. Thus, voters can decide if everyone lived up to their promise.
You think logrolling doesn't happen in the American system? Parties are made up of factions who will entertain each other's preferred priorities, which is the exact same thing you're describing except that the parties of the various factions are nominally the same. There's no real natural or obvious philosophical reason why your position on gun ownership should imply a position on environmental regulation, religion, infrastructure buildings, racial politics, abortion, tax policy, and more. We're so used to the groupings that they seem natural but if we go back and looking at older American party systems you'll see parties that don't 100% map onto the contemporary ones, with a blend of some elements we would think of as fitting and others we wouldn't.