The absence of a legal mechanism does not imply the absence of a mechanism (or even the absence of a peaceful mechanism.)

While there is a legal process for amending the Constitution which, as you note, is likely intractable in the status quo conditions, Constitutional change—whether peaceful (even if there is the implicit consequence of force if compromise is not reached) or not—historically and globally is often an extralegal process that is retrospectively legalized, rather than a legal process under pre-existing rules.