If you could change three things in the US constitution...

[True Federalist (진정한 연방 주의자)]

1. Elect three Senators from each State, one every two years for a two-year term.

2. Make explicit that the Supreme Court can rule laws to be unconstitutional, but require a three-fifths majority for them to do so. (That would six justices with the current size of nine, but if the court's size was expanded to thirteen (one per circuit) then eight of thirteen would be needed instead of nine as would be the case with a two-thirds requirement.

3. Give DC representation in Congress as if it were a State.

[True Federalist (진정한 연방 주의자)]

What's with all the desire for PR for the House?  The size of the House would need to be considerably increased, well beyond a thousand, to have it work while keeping apportionment by States, and apportionment of the House by States is a minimal necessity for keeping our government a Federal one. For a country as large and diverse as ours is, a Federal system is a necessity, not merely a nicety.

[True Federalist (진정한 연방 주의자)]

What's with all the desire for PR for the House?  The size of the House would need to be considerably increased, well beyond a thousand, to have it work while keeping apportionment by States, and apportionment of the House by States is a minimal necessity for keeping our government a Federal one. For a country as large and diverse as ours is, a Federal system is a necessity, not merely a nicety.

Why? The federal government could easily organize federal elections without affecting the power of the states in other areas.

A Federal system needs its elected members to have ties to its local constituents, otherwise its constituent states have practically no way to impact Federal policy.  We already have a system that is too strongly tilted towards the central government as it is, no need to make it worse with a National PR system that would most likely lead to the abandonment of a Federal government and replace it with a National government.

As for why not PR by States, there are 7 States (8 if we give DC representation as a State that have only 1 Representative, and another 4 that have have only 2.  PR simply will not work as desired with those sorts of numbers.  If there were only one or two small entities as is the case in Italy, it would be less of a problem, but that is not the case with the US.

Now, as a compromise of sorts, tho I doubt few would care for it, which is why I didn't mention it my top 3, I could see returning the election of Senators to the State governments, in exchange for limiting its legislative functions to the approval of laws that directly impact State governments.  I.e., budgets to fund already authorized programs, and laws that do not affect State governments in any manner would only need approval by the House, but otherwise current Senate power would be unaffected. (i.e. confirmation of appointments, ratification of treaties, trying of impeachment cases, etc.)

[True Federalist (진정한 연방 주의자)]

End woman's suffrage.

Nah.  Let's end men's suffrage as well and let the robots rule.  Al Gore deserves a chance after all.

[True Federalist (진정한 연방 주의자)]

1. Right to Life Amendment

So you'd abolish the death penalty and establish a right to government provided health care?

[True Federalist (진정한 연방 주의자)]

1. Enact Equal Rights Amendment extending protections to women and LGBT.
2. Scrap the 2nd Amendment empowering local jurisdictions to enact laws.
3. Tighten 'Freedom of Religion' to ensure that freedom from religion is protected in the public sphere.

What exactly do you have in mind for number 3?

Congress shall make no law respecting an establishment of religion, prohibiting the free exercise or repudiation thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.

I'm not opposed to your change of language, but I'm not aware of Congress attempting to prohibit the repudiation of religion?

Besides,  the existing First Amendment is already being interpreted by the courts as protecting the rights of atheists.

[True Federalist (진정한 연방 주의자)]

So?!?

As for why not PR by States, there are 7 States (8 if we give DC representation as a State) that have only 1 Representative, and another 4 that have have only 2.  PR simply will not work as desired with those sorts of numbers.  If there were only one or two small entities as is the case in Italy, it would be less of a problem, but that is not the case with the US.

[True Federalist (진정한 연방 주의자)]

So?!?

As for why not PR by States, there are 7 States (8 if we give DC representation as a State) that have only 1 Representative, and another 4 that have have only 2.  PR simply will not work as desired with those sorts of numbers.  If there were only one or two small entities as is the case in Italy, it would be less of a problem, but that is not the case with the US.

You are just plain wrong. In 1986 France had 20 Départements electing 2 deputies (their average seat/dep count being, as I said, lower than in the US), and PR worked just fine.

And how many of those 2 departments had 1 PS deputy and 1 RPR-UDF deputy?  A system that practically guarantees the left and right will split the seats evenly in a large number of districts is not functionally PR.  Both the PS and the RPR-UDF got considerably more seats than they would have under a nationwide PR system, yet the reason for going to PR is to avoid having politics dominated by two polarized blocks.  The 1986 French election failed to achieve that goal.