An Invalid Amendment by Statute

Article I, Section 2:

"Representatives [...] shall be apportioned among the several States which may be included within this Union,

according to their respective Numbers, which shall be the whole number of free Persons, excluding Indians not taxed.

The Number of Representatives shall not exceed one for every thirty Thousand,

but each State shall have at Least one Representative.[...]"  

This section restores a Constitutional clause after Congress invalidly repealed it by the Reapportionment Act of 1929

(ch 28, 46 Stat. 21, 2 USC Section 2a; updating Pub. L. 62-5 (1911)). 

The Constitution may only be amended by Article V Amendment, not by statute

(see Statute vs Constitutional Amendment and Valid Amendment).

Enforcement of Article V is addressed in Section 5 (see Restoring Invalidly Amended Text).

The Preamble (proposed for restoration):

"We the People of the United States, in Order to [...] establish Justice  

[…] and secure the blessings of Liberty for ourselves and for our Posterity, 

do ordain and establish this Constitution [...]"  

The Preamble asserts the public's right to ordain and establish our government to establish justice

(see The Most Important Clause in American Law).

Article IV's Section 2 derives from it, as does Amendment XIV, Section 1.

These require the government to treat the citizens of all states equally, and to treat the citizens of all states equally.

They guarantee fair and equal reapportionment. 

                                                                                  Article IV, Section 2:

"The Citizens of each State shall be entitled

to all Privileges and Immunities of Citizens in the several States."

Amendment XIV, section 1:

"[...] No State shall make or enforce any law which shall abridge 

the privileges or immunities of citizens of the United States; [...] 

Amendment XIV also requires the government and law to treat all people equally within each state.

Amendment XIV, section 1:

"[...] nor deny to any person within its jurisdiction the equal protection of the laws." 

Since states also enforce federal laws, this covers state and federal laws,

and since Article IV, Section 2 is the law,

Amendment XIV requires all persons to be treated equally by state and federal law in all states.

The Constitution defines apportionment as a representation matter, not an electoral matter.

Since Article I, Section 4 empowers states to set voting criteria those aren't subject to Amendment XIV’s general equality clauses,

only to clauses specific to voting or to governance functions (see Foreign Nationals and Voting, Voting as a Right),

and to the Justice clause itself.

The Framers found the Electoral and Guarantee clauses to consist with dividing representatives equally

among all constituents, not just voters.

Article I already includes all people, citizen or not, in apportionment (see The Representation Question).

Article I, 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, […]” 

Article IV, Section 4:

"The United States shall guarantee to every State in this Union a Republican Form of Government, [...]"

All of these provisions require fair and equal reapportionment. 

Reducing representation over time also violates the Posterity clause.

The United States government was ordained to ensure the people’s rights and powers would last, not decrease. 

Consent to government is also relevant to reapportionment (see Frozen Apportionment and Pop Quiz).