On July 19, President Bush issued the first veto of his presidency on a bill to provide federal funding of stem-cell research. It is a good example of why presidents were given veto power by the Constitution.

I am reminded of some advice once given by former Sen. Bob Dole, Republican of Kansas. "You can never go wrong," he said, "voting for a bill that fails or against a bill that passes."

I've always remembered that because it was so true. The people who want a bill to pass will not mind if you voted against it as long as they end up getting it anyway. But the people who were opposed to the bill will remember that you stood with them.

I also remembered Dole's advice because it's one of those weird things that can be completely true for an individual, but cannot be generalized. Obviously, it is impossible for every member of Congress to vote for a bill that fails, nor can they all vote against a bill that passes.

Getting back to the veto, this is one way a majority of Congress can have their cake and eat it, too. They can support a politically popular bill that many would otherwise be compelled to vote against, knowing that the president will take the heat for keeping it from becoming law. There might have been many fewer votes for the stem-cell bill without the assurance of a veto.

Looking back over the history of presidential vetoes, it is clear that there was a lot of winking and nodding going on between Congress and the White House. Presidents often gave it a pass, allowing members to vote for bills that would aid them politically, but which were bad policy. By vetoing such bills, everyone was happy. And if presidents used a pocket veto, it couldn't be overridden, so Congress was saved from having to even try.

Franklin D. Roosevelt was the all-time champion at playing this game, issuing a record 635 vetoes, the bulk of which were pocket vetoes, despite large Democratic majorities throughout his presidency. Many of these were on private relief bills that the congressional leadership let slide through only because they were assured of a veto.

Over the years, the ability of Congress and the White House to play this mutual back-scratching game has diminished for various reasons. A key one is that Congress passes many fewer bills than it used to. Legislating tends to be done largely by amendment to large bills that are harder to veto.

This has increased Congress's power relative to the president, but it has also cost Congress the opportunity to play the Dole game. It is harder for it to say no to anyone, giving rise to increasing numbers of pork-barrel projects and special deals that are unjustified on public policy grounds. This is why Bush has repeatedly asked for line item veto authority.

The problem is that it isn't only in appropriations bills where problems lie. Moreover, much of the waste in this area is already under the president's control because the spending is specified in what is called report language that does not carry the force of law. Bush could in effect veto this stuff now if he wanted to. Because of his support for so many big spending initiatives, such as the Medicare drug bill, Bush lacks credibility as a guardian of the public purse, making it appear as if his calls for a line item veto are just a way of diverting attention from his own failure to control spending.

In response, the White House points to the fact that Bush often issues veto threats -- 135 times through May, according to the Office of Management and Budget. But with no actual vetoes ever forthcoming, such threats have lost a great deal of credibility over time. Congress now mostly ignores them.

It has always amazed me that a president who understands so clearly that diplomacy must be backed by force to be effective in the international arena should be so oblivious to the fact that the same thing applies domestically as well -- veto threats must be backed by actual vetoes from time to time if they are to be credible. I believe that just one veto of a spending bill back in 2001 would have saved the nation from tens of billions of dollars of wasted spending.

When conservatives complain to the White House about its veto-phobia, they are always told that Republican control of Congress is the main reason. But as Brookings Institution scholar Kathryn Dunn Tenpas points out in a new paper, in the postwar period, presidents before Bush averaged two vetoes per year during times when their own party controlled Congress. Bush is clearly an anomaly.