America would have a better system of government if we'd stuck with Britain
Honestly, I think earlier abolition alone is enough to make the case against the revolution, and it combined with less-horrible treatment of American Indians is more than enough. But it's worth taking a second to praise a less important but still significant consequence of the US sticking with Britain: we would've, in all likelihood, become a parliamentary democracy rather than a presidential one.
And parliamentary democracies are a lot, lot better than presidential ones. They're
significantly less likely to collapse into dictatorship because they don't lead to irresolvable conflicts between, say, the president and the legislature. They lead to much less gridlock.
In the US, activists wanting to put a price on carbon emissions spent years trying to put together a coalition to make it happen, mobilizing sympathetic businesses and philanthropists and attempting to make bipartisan coalition — and they still failed to pass cap and trade, after millions of dollars and man hours. In the UK, the Conservative government decided it wanted a carbon tax. So
there was a carbon tax, and
the coal sector has taken a beating. Just like that. Passing big, necessary legislation — in this case, legislation that's
literally necessary to save the planet — is a whole lot easier with parliaments than with presidential systems.
There are of course exceptions — you need only look at Theresa May’s years of struggle to put together a Brexit package that satisfies her party. But it’s notable that that fiasco began with a deviation from parliamentary government, when David Cameron decided to punt the question of leaving the European Union to the voters. It was the introduction of another unnecessary decisionmaking entity, very common in the veto point-heavy US system, that created the crisis in the first place.
This is no trivial matter. Efficient passage of legislation has huge humanitarian consequences. It makes measures of planetary importance, like carbon taxes, easier to get through; they still face political pushback, of course — Australia's tax got repealed, after all — but they can be enacted in the first place, which is far harder in the US system. And the efficiency of parliamentary systems enables larger social welfare programs that reduce inequality and improve life for poor citizens. Government spending in parliamentary countries is
about 5 percent of GDP higher, after controlling for other factors, than in presidential countries. If you believe in redistribution, that's very good news indeed.
The Westminister system of parliamentary democracy also benefits from weaker upper houses. The US is saddled with a Senate that gives Wyoming the same power as California, which has more than 66 times as many people. Worse, the Senate is equal in power to the lower, more representative house. Most countries following the British system have upper houses — only
New Zealand was wise enough to abolish it — but they're far, far weaker than their lower houses. The Canadian Senate and the House of Lords affect legislation only in rare cases. At most, they can hold things up a bit or force minor tweaks. They aren't capable of obstruction anywhere near the level of the US Senate.
Finally, we'd still likely be a monarchy, under the rule of Elizabeth II, and constitutional monarchy is the best system of government known to man. Generally speaking, in a parliamentary system, you need a head of state who is not the prime minister to serve as a disinterested arbiter when there are disputes about how to form a government — say, if the largest party should be allowed to form a minority government or if smaller parties should be allowed to form a coalition, to name a
recent example from Canada. That head of state is usually a figurehead president elected by the parliament (Germany, Italy) or the people (Ireland, Finland), or a monarch. And
monarchs are better.
Monarchs are more effective than presidents precisely because they lack any semblance of legitimacy. It would be offensive for Queen Elizabeth or her representatives in Canada, New Zealand, etc. to meddle in domestic politics. Indeed, when the governor-general of Australia did so in 1975 it
set off a constitutional crisis that made it clear such behavior would not be tolerated. But figurehead presidents have some degree of democratic legitimacy and are typically former politicians. That enables a greater rate of shenanigans — like when Italian President Giorgio Napolitano schemed, successfully, to
remove Silvio Berlusconi as prime minister due at least in part to German Chancellor Angela Merkel's entreaties to do so.
Napolitano is the rule, rather than the exception. Oxford political scientists Petra Schleiter and Edward Morgan-Jones have
found that presidents, whether elected indirectly by parliament or directly by the people, are likelier to allow governments to change without new elections than monarchs are. In other words, they're likelier to change the government without any democratic input at all. Monarchy is, perhaps paradoxically, the more democratic option.
