WASHINGTON (AP) -- Three lower courts have ruled illegal President Donald Trump's use of emergency powers to impose worldwide tariffs. Now the Supreme Court, with three justices Trump appointed and generally favorable to muscular presidential power, will have the final word.

In roughly two dozen emergency appeals, the justices have largely gone along with Trump in temporarily allowing parts of his aggressive second-term agenda to take effect while lawsuits play out.

But the case being argued Wednesday is the first in which the court will render a final decision on a Trump policy. The stakes are enormous, both politically and financially.

Trump has made tariffs a central piece of his economic and foreign policy, and has said it would be a "disaster" if the Supreme Court rules against him.

Here are some things to know about the tariffs arguments at the Supreme Court:

They are paid by companies that import finished products or parts, and the added cost can be passed on to consumers.

Through September, the government has reported collecting $195 billion in revenue generated from the tariffs.

The Constitution gives Congress the power to impose tariffs, but Trump has claimed extraordinary power to act without congressional approval by declaring national emergencies under the 1977 International Emergency Economic Powers Act.

In February, he invoked the law to impose tariffs on Canada, Mexico and China, saying that the illegal flow of immigrants and drugs across the U.S. border amounted to a national emergency and that the three countries needed to do more to stop it.

In April, he imposed worldwide tariffs after declaring the United States' longstanding trade deficits "a national emergency."

Challengers to Trump's actions won rulings from a specialized trade court, a district judge in Washington and a business-focused appeals court, also in the nation's capital.

Those courts found that Trump could not justify tariffs under the emergency powers law, which doesn't mention them. But they left the tariffs in place in the meantime.

The appeals court relied on " major questions," a legal doctrine devised by the Supreme Court that requires Congress to speak clearly on issues of "vast economic and political significance."

Conservative majorities struck down three separate initiatives related to the coronavirus pandemic. The court ended a pause on evictions, blocked a vaccine mandate for large businesses and prevented student loan forgiveness that would have totaled $500 billion over 10 years.

In comparison, the stakes in the tariff case are much higher. The taxes are estimated to generate $3 trillion over 10 years.

The challengers in the tariffs case have cited writings by the three Trump appointees, Justices Amy Coney Barrett, Neil Gorsuch and Brett Kavanaugh, in calling on the court to apply similar limitations on a signal Trump policy.

Barrett described a babysitter taking children on roller coasters and spending a night in a hotel based on a parent's encouragement to "make sure the kids have fun."

"In the normal course, permission to spend money on fun authorizes a babysitter to take children to the local ice cream parlor or movie theater, not on a multiday excursion to an out-of-town amusement park," Barrett wrote in the student loans case. "If a parent were willing to greenlight a trip that big, we would expect much more clarity than a general instruction to 'make sure the kids have fun.'"

Kavanaugh, though, has suggested the court should not apply the same limiting standard to foreign policy and national security issues.

A dissenting appellate judge also wrote that Congress purposely gave presidents more latitude to act through the emergency powers law.

Some of the businesses that sued also are raising a separate legal argument in an appeal to conservative justices, saying that Congress could not constitutionally delegate its taxing power to the president.

The so-called nondelegation principle has not been used in 90 years, since the Supreme Court struck down some New Deal legislation.

But Gorsuch authored a dissent in June that would have found the Federal Communications Commission's universal service fee an unconstitutional delegation. Justices Samuel Alito and Clarence Thomas joined the dissent.

"What happens when Congress, weary of the hard business of legislating and facing strong incentives to pass the buck, cedes its lawmaking power, clearly and unmistakably, to an executive that craves it?" Gorsuch wrote.

The court only agreed to hear the case in September, scheduling arguments less than two months later. The quick turnaround, at least by Supreme Court standards, suggests that the court will try to act fast.

High-profile cases can take a half year or more to resolve, often because the majority and dissenting opinions go through rounds of revision.

But the court can act quickly when deadline pressure dictates. Most recently, the court ruled a week after hearing arguments in the TikTok case, unanimously upholding a law requiring the popular social media app to be banned unless it was sold by its Chinese parent company. Trump has intervened several times to keep the law from taking effect while negotiations continue with China.