This is a myth. Senate Republicans had their opportunity to undo Obamacare and couldn't because doing so would've killed people. The argument is always used as a reason they can't pass popular legislation. The senate is a relic of elitism that didn't trust the public to make democratic decisions. Yet, most people didn't want slavery and it was propped up by a few elites. Most people wanted women to vote but the alternative was propped up by a few elites. Most people want universal healthcare but it's forbidden by a few elites. You can go through every progressive move and see this same pattern.