The supreme court interprets the constitution, and if the supreme court declares that the constitution gives the supreme court absolute power, there is nothing in the constitution to stop the supreme court. The executive and legislative branches could try to impeach the supreme court, but if the supreme court said that the impeachment is invalid, there is nothing in the constitution to stop the supreme court. The power of the supreme court is as little or as much as the supreme court says.
This really happened in the roman republic. The leaders of Rome were elected. The power of the leaders of Rome were limited because everyone had to obey the will of the gods. The will of the gods was interpreted by priests. Then Julius Caesar bribed enough people to get himself appointed chief priest, and then Julius Caesar declared that it was the will of the gods that everyone should obey Julius Caesar, and so Julius Caesar became dictator of Rome and the roman republic became the roman empire.
Defenders of the american constitution say that the power of the supreme court is limited because the supreme court has no influence over making laws, taxes, government spending, and government hiring; and the supreme court cannot rule on issues unless a case is presented to the supreme court. But the supreme court has discovered previously unknown rights in the constitution, and has ordered the government to implement policies to enforce the rights and correct injustices created by previous failure to defend those rights. The effect is the same as if the supreme court made laws. The supreme court can impose fines, and there is little difference between a fine and a tax. The supreme court can and has ordered the government to pay money to various persons and organizations, so the supreme court does control the government budget. If someone seeks a government job but is rejected, the person can sue the government, and the supreme court may order the government to hire the person, so the supreme court does control government hiring. The supreme court cannot rule on an issue until a case is presented to the supreme court, but if the supreme court wants to rule on an issue, then a member of the supreme court could ask a friend to present a case about that issue. There is nothing illegal or unconstitutional about supreme court justices privately encouraging cases which they want to hear.
The supreme court is willing to use any power used by the supreme court in the past. Sometimes the supreme court uses a power which was not used by the supreme court in the past. Then the new power becomes a historical precedent, and the supreme court will be willing to use that power in the future.
The power of the supreme court never decreases, and slowly increases. Eventually the supreme court will have absolute power. Based on how much power the supreme court has accumulated up to now (I am writing this in 2005), I estimate that it will take about one hundred years for the supreme court to acquire absolute power.
You may think that one hundred years is a long time, and we should not worry because we will be dead before the supreme court acquires absolute power. My point is that the american constitution is not a constitution for all time, like its defenders claim. The american constitution has serious flaws which will eventually cause the constitution to fail.
Also, the american constitution should not be used as a model for the constitutions of other nations.
Someday we will have to fix the constitution. Why not now?