Last week's news from Washington: A dysfunctional Congress managed to function just long enough to bludgeon President Obama into ceding his prerogative to enter into an executive agreement with Iran regarding its nuclear program.

That's unfortunate. I wish the president had had the votes to hang tough on this important right, in part because of the precedent it sets for future executive agreements and the pall it casts over his fight for the legality of his recent executive orders on immigration, climate change and other matters.

Over the past four decades, Congress — with an occasional assist from the courts — has gradually, and regrettably, eroded the powers of the presidency.

Take, as one small example, Obama's sensible proposal in 2012 to consolidate several departments and agencies into a new Cabinet department that would manage trade and business-related functions. Until 1984, a president could have implemented this type of reorganization on his own authority, just as private-sector chief executives routinely do. However, with the expiration of a Depression-era law, the president needed Congress' assent, and Congress was in no mood to give it, in part because the powerful Senate Finance Committee would have lost some of its oversight responsibility.

The need to reverse the slide in presidential authority would perhaps be less urgent if Congress were actually doing anything. But the last two Congresses have passed fewer than 300 laws each, the fewest in modern history. By comparison, the famous "do-nothing" Congress of 1947-48 passed 906 laws.

I saw the problem firsthand when I served in the Treasury early in the Obama administration. Obama was able to inject about $80 billion into the automobile industry without congressional approval because, in a panicked moment in the fall of 2008, Congress had given George W. Bush's administration a $700 billion virtually discretionary rescue fund. But when it came to similar challenges — such as reforming the insolvent housing finance giants Fannie Mae and Freddie Mac — the administration was powerless. Today, more than six years after the Bush administration correctly put them into "temporary" conservatorship, they sit exactly as they did in 2008, as if preserved in amber.

The assault on presidential authority dates from at least the early 1970s, when a mix of the Vietnam War, Watergate and a mushrooming executive branch raised fears of an "Imperial Presidency," as the historian Arthur M. Schlesinger Jr. titled his influential 1973 book.

While the War Powers Resolution of 1973 is perhaps the best-known product of these fears, Congress also restricted the president's ability to withhold funds that had been appropriated. In addition, Congress required that the text of any new international executive agreement be sent to it promptly.

Nonetheless, the president's authority to enter into executive agreements has remained in place and has been widely used in recent years: 2,058 times by Bill Clinton, 1,876 times by Bush and 791 times by Obama (as of 2012).

While many of these agreements are minor, significant actions have been taken using this authority, including those that ended America's involvement in the Vietnam War in 1973, freed the hostages in Iran in 1981 and set a timetable for the withdrawal of troops from Iraq by 2011.

Presidents have been routinely frustrated by their lack of authority. Woodrow Wilson, before he became president, wrote a book extolling the virtues of a parliamentary system. As a young New York Times reporter living in Britain, I saw the merits of a unified government. When the prime minister proposes a new budget, it normally passes within a few months. By comparison, Congress hasn't passed a budget since 2009. The British example also shows that our system of checks and balances is not required to safeguard against a runaway leader.

Now, I recognize that a Congress that has trouble passing any legislation isn't going to start rewriting the Constitution. However, we can do better than the current presidential impotence, particularly if both sides recognize that what goes around comes around.

So let's reinstate the president's ability to implement routine reorganizations. Let's not use last week's encroachment on presidential power as a precedent to challenge executive agreements. Let's stop the frivolous lawsuits over his executive orders.

And let's restore the line-item veto, which would provide the president with better control of spending. Uncharacteristically, Congress conferred that authority on the president in 1996, but the Supreme Court ruled the law unconstitutional. Nearly four years ago, with bipartisan support, a bill was passed by the House that would work around the legal problem and restore the line-item veto. It has yet to reach the Senate floor.

We need a stronger presidency, regardless of whether the occupant is a Democrat or a Republican.

Steven Rattner is a Wall Street executive. He wrote this article for the New York Times.