The Economic Growth and Tax Relief Reconciliation Act of 2001 (EGTRRA) & The Jobs and Growth Tax Relief Reconciliation Act of 2003 (JGTRRA)

"The Economic Growth and Tax Relief Reconciliation Act of 2001 (EGTRRA)
& The Jobs and Growth Tax Relief Reconciliation Act of 2003 (JGTRRA)

One of the most notable characteristics of EGTRRA
is that its provisions are designed to sunset,
or revert to the provisions that were in effect before it was passed.

...The sunset provision sidesteps the Byrd Rule,
a Senate rule that amends the Congressional Budget Act
to allow Senators to block a piece of legislation
if it purports to significantly increase the federal deficit beyond a ten-year term.

The sunset allowed the bill to stay within the letter of the PAYGO law
while removing nearly $700 billion
from amounts that would have triggered PAYGO sequestration.

EGTRRA generally reduced the rates of individual income taxes:

A new 10% bracket was created for single filers
with taxable income up to $6,000,
joint filers up to $12,000,
and heads of households up to $10,000.

the 15% bracket's lower threshold was indexed to the new 10% bracket

the 28% bracket would be lowered to 25% by 2006

the 31% bracket would be lowered to 28% by 2006

the 36% bracket would be lowered to 33% by 2006

the 39.6% bracket would be lowered to 35% by 2006

The Jobs and Growth Tax Relief Reconciliation Act of 2003 (JGTRRA)
accelerated the gradual rate reduction and increase in credits passed in EGTRRA.

The maximum tax rate decreases originally scheduled to be phased into effect in 2006 under EGTRRA
were retroactively enacted to apply to the 2003 tax year."

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