The global warming debate arrives in the Senate next week, and it's about time. Finally, the Members will have to vote on something real, as opposed to their buck-passing to courts and regulators, and their easy trashing of President Bush.

The vehicle is a bill that principal sponsors Joe Lieberman and John Warner are calling "landmark legislation." They're too modest. Warner-Lieberman would impose the most extensive government reorganization of the American economy since the 1930s.

Thankfully, the American system makes it hard for colossal tax and regulatory burdens to foxtrot into law without scrutiny. So we hope our politicians will take responsibility for the global-warming policies they say they favor. Or even begin to understand what they say they favor. For a bill as grandly ambitious as Warner-Lieberman, very few staff, much less Senators, even know what's in it. The press corps mainly cheerleads this political fad, without examining how it would work or what it would cost. So allow us to fill in some of the details.

Almost all economic activity requires energy, and about 85% of U.S. energy generates carbon dioxide and other greenhouse gases. For centuries, these emissions were considered the natural byproduct of combustion. As recently as the 1990 Clean Air Act amendments, they were consciously not even described as a "pollutant." But now that the politicians want to decrease those emissions, the government must create a new commodity – the right to create CO2 – and put a price on it. This is an unprecedented tax that would profoundly touch every corner of American life.

The policy preferred by the environmental lobby is called cap and trade. The government would set a limit on emissions that declines every year. The goal of Warner-Lieberman is to return to 2005 levels by 2012, and to reduce that by 30% by 2030.

"Allowances" for emissions would be distributed to covered businesses – power, oil, gas, heavy industry, manufacturing, etc. If they produced less than their allotment, the companies could sell the allowances, or trade them. Cap and trade limits on energy are thus sometimes misleadingly described as a "free market" policy that would create the flexibility for CO2 reductions how and where they are least expensive. But the limits are still a huge tax.

And for the most part, the politicians favor cap and trade because it is an indirect tax. A direct tax – say, on gasoline – would be far more transparent, but it would also be unpopular. Cap and trade is a tax imposed on business, disguising the true costs and thus making it more politically palatable. In reality, firms will merely pass on these costs to customers, and ultimately down the energy chain to all Americans. Higher prices are what are supposed to motivate the investments and behavioral changes required to use less carbon.

The other reason politicians like cap and trade is because it gives them a cut of the action and the ability to pick winners and losers. Some of the allowances would be given away, at least at the start, while the rest would be auctioned off, with the share of auctions increasing over time. This is a giant revenue grab. The Congressional Budget Office estimates that these auctions would net $304 billion by 2013 and $1.19 trillion over the next decade. Since the government controls the number and distribution of allowances, it is also handing itself the political right to influence the price of every good and service in the economy.

The Environmental Protection Agency estimates that this meddling would cause a cumulative reduction in the growth of GDP by between 0.9% and 3.8% by 2030. Add 20 years, and the reduction is between 2.4% and 6.9% – that is, from $1 trillion to $2.8 trillion.

These estimates assume that electricity prices will increase by 44% above what they would otherwise be by 2030. They also assume that existing coal-fired power plants, which currently provide about 50% of U.S. electric power, will be shut down – to be replaced with at least 150% growth in new nuclear facilities, plus other "alternatives." Yet there are only 104 current U.S. nuclear plants, and the industry itself says it's optimistic to think even 30 more can be built by 2020.

In fact, it is pointless to project so far out over multiple decades, since no one knows how markets and consumers would respond, whether the rules would remain constant, or what new technologies might come along. While moralizing about America, most of Europe has failed to meet its mandatory cap and trade goals under the Kyoto Protocol. But the U.S. isn't Italy; we will enforce our laws. So our guess is that these cost estimates are invariably far too low.

In a bow to this reality, California Democrat Barbara Boxer last week introduced 157 pages of amendments to Warner-Lieberman. Most notably, she sets aside at least $800 billion through 2050 for consumer tax relief. So while imposing a huge new tax on all Americans, she vouchsafes to return some of the money to some people. Needless to say, the Senator will be the judge of who receives her dispensation.

Ms. Boxer's amendment shows that cap and trade is also a massive wealth redistribution scheme – all mediated by her and her fellow Platonic rulers. Oh, and she also includes an "emergency off-ramp," should costs prove too onerous. This is really a political "off-ramp" to make Warner-Lieberman seem less dangerous, but you can imagine her reaction if some future Republican President decided to take it.

The upshot is that trillions in assets and millions of jobs would be at the mercy of Congress and the bureaucracy, all for greenhouse gas reductions that would have a meaningless impact on global carbon emissions if China and India don't participate. And only somewhat less meaningless if they do.

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Warner-Lieberman has no chance of becoming law this year with President Bush in the White House. But the goal of this Senate exercise is political – to get Members on the record early, preferably before the burdens of cap and trade become more widely understood; to give Democrats a campaign issue; and to pour the legislative foundation that the next Administration could cite as it attempts to regulate carbon limits while waiting for Congress to act.

So by all means let's have this debate amid $4 gasoline, and not only on C-Span. If Americans are going to cede this much power to the political class, they at least ought to do it knowing the price they will pay.