In a rare Sunday session of the United States Senate on August 7, 2022, Vice President Kamala Harris -- a Democrat -- cast the tie-breaking vote in a 50-to-50 vote between Democrats and Republicans, ending with a 51-to-50 vote in favor of the Democrats. Democrats used a fast-track legislative process known as reconciliation to pass the measure in the face of unanimous opposition from Republicans.
In the one-page summary, "The Inflation Reduction Act of 2022", published by the U.S. Senate on their website, it states:
The Inflation Reduction Act of 2022 will make a historic down payment on deficit reduction to fight inflation, invest in domestic energy production and manufacturing, and reduce carbon emissions by roughly 40 percent by 2030. The bill will also finally allow Medicare to negotiate for prescription drug prices and extend the expanded Affordable Care Act program for three years, through 2025.
To fully understand why both Democrats and Republicans feel as strongly as they do about certain legislation in Congress, and why they mostly vote along party lines, one has to understand the mind-set of both political parties, and the differences between demand-side economics and supply-side economics.
In demand-side economics, government increases its spending. For example, by investing in infrastructure, and building new highways and bridges, or replacing old ones. This creates jobs, and puts money into consumers' hands. Consumers now have more money to spend -- which creates demand -- and increases production in consumer goods, stimulating the economy.
In supply-side economics, government cuts taxes on business and the wealthy. With more money available for spending, they invest it in production and manufacturing. An increase in production and manufacturing -- the supply side -- creates jobs, and those workers have more money to spend on consumer goods, stimulating the economy.
Democrats in Congress favor demand-side economics because it increases spending in federal programs, which creates job growth and increases consumer demand. This provides spending money to those who generally side with the Democratic party -- the average worker.
Republicans in Congress favor supply-side economics because tax cuts on business doesn't require the creation of a new federal program. And with the tax cuts, business can easily increase its production. And the tax cuts go to those who generally side with the Republican party -- big business.
Both of these methods work. It just depends on which political party is in the White House, and which political party is in control of Congress.