WASHINGTON — Former Supreme Court justice John Paul Stevens wants to reduce gun violence, abolish the death penalty, restrict political campaign spending, limit states’ independence and make Congress more competitive and less combative.

His solution: Amend the Constitution.

Four years into a hard-earned retirement after serving 35 years on the nation’s highest court, Stevens is still speaking out, writing books and book reviews, even swimming in the ocean as long as someone’s nearby to help him out. His latest book, Six Amendments: How and Why We Should Change the Constitution, calls attention to some of the nation’s most intractable problems.

The bow-tied Stevens, who turned 94 on Sunday, is using the publication of his second book as an opportunity to reflect not only on his literary efforts but also on today’s justices, the complex cases they face, and the issues likely to reach the court in the near future, from same-sex marriage to government surveillance.

His main focus is on a half-dozen issues that he believes have been wrongly decided or avoided — issues that can best be addressed by altering a document that’s been amended only 18 times in history, and just once since he joined the court in 1975.

“It’s certainly not easy to get the Constitution amended, and perhaps that’s one flaw in the Constitution that I don’t mention in the book,” he said during a wide-ranging interview with USA TODAY in his chambers at the court. Noting his book’s half dozen proposed amendments, he mused, “Maybe I should have had seven.”

Among the amendments Stevens suggests:

•Changing the Second Amendment to make clear that only a state’s militia, not its citizens, has a constitutional right to bear arms.

•Changing the Eighth Amendment’s prohibition against “cruel and unusual punishments” by specifically including the death penalty.

•Removing from First Amendment protection any “reasonable limits” on campaign spending enacted by Congress or the states.

•Requiring that congressional and state legislative districts be “compact and composed of contiguous territory” to stop both parties from carving out safe seats.

•Eliminating states’ sovereign immunity from liability for violating the Constitution or an act of Congress, which he calls a “manifest injustice.”

•Allowing Congress to require states to perform federal duties in emergencies, in order to reduce “the risk of a national catastrophe.”

It was the December 2012 school shootings in Newtown, Conn., that focused Stevens’ attention on a rule that prevents Congress from requiring states to perform federal duties. The rule had led to holes in a federal database of gun purchases.

“It’s called the anti-commandeering rule, which turned out to be the first chapter of a book that kind of grew like Topsy,” Stevens said. “I thought that maybe the only way to get rid of the rule is to have a constitutional amendment, and then it occurred to me … that there really are other provisions of the Constitution that should be looked at more closely.”

Though Stevens proposes precise language for each proposed amendment, he admits the process is extremely difficult. It takes two-thirds of both houses of Congress or state legislatures to propose an amendment and three-fourths of the legislatures to approve it. The last amendment, blocking Congress from changing its members’ salaries between elections, passed in 1992.

“I’m not the kind of optimist that expects this all to happen in the next couple of years,” he said.

In the meantime, the third-longest serving justice in history will continue working a couple of days a week in his book-lined chambers while splitting time between the nation’s capital and Fort Lauderdale. He makes occasional trips to his native Chicago to visit three generations of offspring. “Don’t even ask me to count them all up right now,” he pleaded.

“I haven’t had a single regret” since retiring in 2010, Stevens said. That’s due largely to his respect for his replacement, former Harvard Law School dean and U.S. solicitor general Elena Kagan.

“There are a few times where I would have decided a case differently than she has,” he acknowledged, but “she’s a beautiful writer. She’s doing a fine job.”

Stevens cautioned against labeling what’s become known as “the Roberts Court,” after conservative Chief Justice John Roberts. While the four liberal justices usually are allied, the five conservatives often don’t stick together. Antonin Scalia is a renegade on criminal defense issues, Samuel Alito in some First Amendment cases, Anthony Kennedy on questions of equal protection and due process, and Roberts himself cast the deciding vote to uphold President Obama’s health care law in 2012.

Even Clarence Thomas, a reliable conservative, is often misunderstood, Stevens said. “He’s often unfairly judged as not being prepared because he never says a word during oral argument,” he said. “But I can tell you he has read the briefs and thought the case through before he votes in conference, and before the argument starts.”

Among the issues to watch for, he said, are a constitutional right to same-sex marriage (“Sooner or later, they’ll have to address the question”), gun control (Scalia’s 2008 opinion protecting handguns in the home won’t be the final word), and government surveillance programs, which Stevens defends as constitutional.

As for bringing cameras into the court chamber, Stevens is a traditionalist. “If you leave it up to members of the court, I don’t think there’s a chance in the foreseeable future,” he said. “The downside is that whenever you bring television into a new arena, you’re never sure what’s going to happen.”

The downside of growing old, Stevens has discovered, is that he’s finally slowing down. A “bum knee” requires regular cortisone shots. His wife Maryan’s worsening health has cut back on their trips to Chicago. Even in Florida, “I found this year that it was not wise to go in the ocean if I didn’t have a friend available to help me get out.”

There’s still golf, perhaps a little tennis, and a lot of reading. He just finished The Bully Pulpit: Theodore Roosevelt, William Howard Taft, and the Golden Age of Journalism by Doris Kearns Goodwin, and he’s almost through former Defense secretary Robert Gates’ recent Duty: Memoirs of a Secretary at War. For Stevens, each book is filled with new discoveries.

Even at 94, he said, “it’s amazing how many interesting things there are to learn about the world.”