"The president is the sole representative and spokesperson of the states" can bypass the entrenched clause.
But something obvious the senate can block is not it. An amendment that gives the presidemt power to suspend congress during a national crisis or for national securitu will do the trick too, it is a bit obvious but people might be ok with it if a crisis or war is big enough. The only thing preventing a dictatorship is the senate who serve longer terms than the president. Being able to suspend the senate (the VP had a role!?) without an amendment is even more powerful if the majority party is for the dictatorship. General elections can be delayed indefinetly.
