He literally said terminate the rules including those in the U.S. Constitution.
According to the Constitution:
Section 4
The Times, Places and Manner of holding Elections for Senators and Representatives,
shall be prescribed in each State by the Legislature thereof; but the Congress may at
any time by Law make or alter such Regulations, except as to the Places of chusing
Senators.
The Congress shall assemble at least once in every Year, and such Meeting shall be
on the first Monday in December, unless they shall by Law appoint a different Day.
The Constitution gives some leeway to Congress in order to augment the rules in the document. Trump is correct in stating the rules should be evaluated and possibly changed. If that required a Constitutional Convention, it would take too long.
The genius in what the founders created is that it CAN be changed.
They understood that no man or government can predict the future, nor are they so wise that they are infallible.
There are 27 Amendments to the Constitution. In nearly 250 years, the nation has seen fit
to make changes 27 times. The process to amend the document is as difficult as it is for a reason -- changes should not be made for political reasons, but to correct errors or to keep up with relevant societal changes, like the abolition of slavery.
Trump suggesting that the Constitution doesn't stop the states from cheating in elections is an opinion -- which is his right as an American to express,
You, on the other hand, have only hate and lies.
I bet if someone advocated for changing the Constitution so abortion and healthcare become rights, you'd be all for it.