James Simon is a professor and dean emeritus at New York Law School. His new book, "FDR and Chief Justice Hughes," tracks the battle between Franklin Delano Roosevelt and the chief justice of a Supreme Court that seemed, at the outset of the New Deal, to be determined to reject most anything significant FDR did. I spoke with Simon this morning. A lightly edited transcript of our conversation follows.

Ezra Klein: There have been a number of analogies drawn between FDR’s struggles with the Supreme Court in the 1930s and President Obama’s struggles today. Do you think they’re fair?

James Simon: The analogies are important. The two courts are more polarized ideologically than at other times in modern constitutional history. In the 1930s, there were four ideological conservatives on the court, known as the Four Horseman. They were very much committed to a laissez faire constitutional and political philosophy, and fairly systematic in their opposition to government regulation. There were then three liberals on the court led by the great Justice Louis Brandeis. In the middle, there were two pivotal centrists. One was Chief Justice Hughes and the other was Justice Roberts. Both of them were appointed by President Hoover.

Fast forward to today’s court and I think it’s fair to say that you have four ideological conservatives. You have four liberals, though I don’t think they have quite the same commitment to an ideology as the conservatives -- which was also true in the 1930s. But they are now, and were then, liberals. And in the middle is Justice Kennedy. So Kennedy in a way serves the same role as Chief Justice Hughes and Justice Roberts in the 1930s.

It seems like a very different situation to have the chief justice as one of the pivotal centrists.

It’s interesting to compare the two chief justices. Hughes was a centrist. He was not an ideologue. And, like Chief Justice Roberts, he was appointed by a Republican president, and like Roberts, he came to the Court after a career as a brilliant lawyer. But Hughes came out of a progressive tradition in the Republican Party. He was a reform governor of New York. he was a strong civil libertarian. When he was secretary of state under President Warren Harding, he was an internationalist. He also believed strongly in trying to bring the court together.

Roberts is a conservative. He comes out of the conservative wing of the Republican Party. And if you look at his record since becoming chief justice, he fairly consistently aligns himself with the conservatives on polarizing issues. So the question today is whether Roberts will align himself with the conservatives or do what Hughes sometimes did in the 1930s and put the image of the court as a nonpartisan institution ahead of strong ideological convictions.

The tensions between FDR and his Supreme Court famously led to Roosevelt’s ill-fated court-packing scheme. I wonder if, after Bush v. Gore and Citizens United, a ruling against the Democrats’ signature legislative achievement wouldn’t potentially activate some kind of response from elected Democrats.

Oh, I think it can. Not in exactly the way it did in the 1930s. In 1936, Roosevelt was reelected in a landslide and had a very strong and popular majority. That emboldened him to try to do something about what he thought was a conservative court majority frustrating the popular will. Let’s say this Supreme Court rules 5 to 4 to strike down either the individual mandate or the Affordable Care Act. There is no question in my mind that President Obama will make that decision front-and-center in the campaign. But he will not do what Roosevelt did in 1937. He will not call for a court reform bill. That was a disaster for Roosevelt.

 Do you believe the story that though FDR’s effort to pack the court failed, it succeeded in intimidating the court into accepting his agenda? I know Chief Justice Hughes disputes that in his memoirs.

I think they were both right. I think the court would have moved in the direction that they ultimately did with Hughes voting with the liberal majority to uphold New Deal legislation after 1937 even if there hadn’t been a court-packing plan. He was very concerned with the image of the court after FDR’s landslide reelection. By the end of the 1936 term, the court was seen as being highly partisan. They had struck down a very popular minimum wage law. They had ruled for a coal firm in an important case for worker’s rights. Hughes was already moving in the direction of trying to reconcile the two wings of the court. Months before FDR announced his court-packing plan, the justices voted to uphold a minimum wage law for women in Washington State that seemed very similar to the one they had just struck down from New York.

That speaks, however, to a major difference between the two periods. In 1936, Roosevelt was massively popular, he had a huge majority in the Congress, and he had strong support from the country for his agenda. The Supreme Court really was on the wrong side of public opinion, and perhaps of the Congress. That’s not clearly true today. Citizens united was a very unpopular decision, but Obama’s numbers are nothing like FDR’s, the health-care law isn’t popular, Republicans control the House of Representatives, and so on. That seems to give the Supreme Court a lot more space to rule how they want.

That’s a fair distinction. Roosevelt came with an overwhelming popular mandate in 1936, whereas Obama did win handily in 2008, but the nation is pretty closely divided on the president’s policies. But still, the concern of Hughes in the 1930s might well be the concern of Roberts in 2012 in this way: A chief justice does not want the court to appear to be deciding public policy on fairly narrow constitutional grounds, and particularly if it goes against some fairly solid precedents in the other direction, and that’s what the court is facing today.  If the court rules 5 to 4 to strike down all or part of the health-care law,  they’re putting themselves in the middle of a public policy dispute in a way the Chief Justice Hughes tried to avoid.

 I want to read you two quotes on what’s happening in the court right now. One comes from my colleague Charles Lane, who writes that “the post-New Deal consensus about the scope of federal power has broken down amid national, and global, concern over the welfare state’s cost and intrusiveness.” As he sees it, the Supreme Court redefined federal power in the 30s amid one sort of consensus, and may be about to redefine it amid another sort of consensus, or perhaps lack of consensus. What do you think?

He may be right. He’s certainly right in the sense that there are members of the court who have never liked the Commerce Clause doctrine. Justice Scalia has said the 1942 decision Wickard v. Filburn was wrong. And certainly Justice Thomas is poised to do that. He has always said he thought the modern Commerce Clause doctrine was misguided and wrong. And I suspect Justice ALito would join them. And that may be the new era.

But then the question comes, once you get five votes, do you simply uproot 75 years of constitutional precedent? If you do that, you’re not showing judicial restraint. You’re a very, very activist court. And then the court makes itself an issue in any political campaign. If a doctrine as important as the Commerce Clause doctrine can be reversed by a single vote or even two votes, without much attention to precedent, then the court becomes another political branch of the government.

Another view came from James Fallows at the Atlantic, who argued that if we saw this in another country, we’d call it a kind of judicial coup. He wrote: “Try this at home. Pick a country and describe a sequence in which: First, the presidential election is decided by five people, who don’t even try to explain their choice in normal legal terms. Then the beneficiary of that decision appoints the next two members of the court, who present themselves for consideration as restrained, humble figures who care only about law rather than ideology. Once on the bench, for life, those two actively second-guess and re-do existing law, to advance the interests of the party that appointed them. Meanwhile their party’s representatives in the Senate abuse procedural rules to an extent never previously seen to block legislation — and appointments, especially to the courts. And, when a major piece of legislation gets through, the party’s majority on the Supreme Court prepares to negate it — even though the details of the plan were originally Republican proposals and even though the party’s presidential nominee endorsed these concepts only a few years ago.”

I don’t think it’ll ever come to that, certainly not in the foreseeable future. But there is that danger. If five members of the court decide to overturn a major piece of legislation that has been passed as the Constitution requires, then the court becomes yet another political branch of the government, which was not the intention of the Founders. But I don’t think it will come to that because I don’t think Kennedy is an ideologue. He’s conservative, but not an ideologue. So it could happen, but I don’t think it’s likely.

I find myself a bit between the two. I don’t think it’s inherently illegitimate for a Supreme Court to radically redefine constitutional law. That’s a power we have given them, and if we don’t like it, it’s a power we can take from them. What really unsettles me is the role they’re playing in elections. They substantially decided the 2000 election through Bush v. Gore, which led to Bush appointing two new Supreme Court Justices. Then they decided Citizens United, which many think could be the reason Obama loses this year. If that happens, then Romney will likely be able to make the court solidly conservative for a generation. Which is to say, I’m comfortable with elections having consequences for the Supreme Court, but when the Supreme Court begins putting its thumb on the scales in elections, that seems more dangerous and unsettling.

I agree with you. I think Bush v. Gore was a clear political decision by the five most conservative members, all appointed by Republican presidents, and even they sort of admit that. They’ve never applied that reasoning to another decision. Justice John Paul Stevens wrote a scathing dissent and he was right. I agree on Citizens United, and I agree on the general direction of the split decisions that are most polarized. This is distorted from what the Founders intended.