Comment by klardotsh
That described Dutch system also sounds relatively easy compared to the US model, which requires 2/3 votes in each chamber of Congress (meaning the people-based one and the land-based one), *then* 3/4 of the states (so another land-based check) have to ratify it.
Functionally this means that in the modern political climate, the US Constitution is fully frozen with no hope of amendment really ever again.
> this means that in the modern political climate, the US Constitution is fully frozen
Would note that this is a very modern phenomenon, with Nixon having considered pushing for abolishing the electoral college in the 70s.