The US president hasn't required a new war resolution since Afghanistan. They each keep stretching it farther and farther. It cannot be rescinded without a veto-proof majority. If there was a veto proof majority willing to stand up to the executive, a conviction and removal would have already occurred.
The assertion that the US is a democracy is nisguided. It will be downgraded by vdem this month to an electoral autocracy. It is also worth noting that it only takes senators receiving the votes of <7% of the total population to filibuster all legislation, prevent overriding any vetos, and halt all impeachment trials. The fact it has looked like a democracy for so long is astounding.