2. Congress has the power to levy taxes (Article I, Section 8, Clause 1 and amongst other places in Article I, Section 8 as well as the 16th Amendment)
3. Constitution does not forbid congress to pass legislation that enables citizens to receive tax credits. And the congress did that by the creation of an agency to help people get health insurance. "Federal and State Exchanges"
4. Therefore, PPACA is well within the power of congress according to the constitution.
The Supreme Court found this to be the case so if you think it's unconstitutional, you'll have to take it up with the Supreme Court. Although, they are highly unlikely to want to hear the case again.
You may think Obamacare is bad, in reality, insurance premiums are high because hospitals have to make up for its huge amounts of bad debt from treating people without insurance and can't play for their treatment. And since hospitals can't refuse emergency room patients, they take a huge loss. Not to mention, it clogs up the Emergency Room so that someone who absolutely needs Emergency Care may not receive it in time. To make up for that, the hospitals charge insurers a huge amount and provides really bad service. The wait time at certain hospital ERs are 4 to 6 hours. To fix the problem. you need to keep people out of the ER, make hospitals charge less.
The PPACA attempts to do that by: 1. Encouraging people to get insurance. It's ok if you don't, you'll just have to pay some more taxes.
2. If you have insurance, you go get seen by a doctor before you have to go to the ER. This reduces the stress on ER and ensures that the hospital's bad debt is reduced.
3. Hospitals are put on a new plan to get paid. Instead of a set fee for providing a service, they are now paid to manage the health of an individual. Before the incentive was to do as many tests and treatments with the patient as possible since the government paid up for each one. Now the hospital is paid a set fee to provide care towards 1 patient per month at a certain standard of care. If they do too many tests, that will eat into their margins. If they do too few tests and the patient gets really sick, then they fail the quality of care test and they get penalized on the payment. Either way, the hospitals will be incentivized to provide good quality of care without going overboard. And this will reduce the cost of care overall, which will in turn reduce healthcare insurance premiums.
Full disclosure: I work for a major pharmaceutical company on the impact of PPACA on their ability to access physicians and sell their products.