It is President Bush’s decision to interdict support for the Iraq insurgency coming from Syria and Iran that is, in our estimation, likely to be the focus of the showdown with the Democrats in the Congress. This is particularly true because the president is determined to act on the authority inherent in the presidency. We were thinking about that over the weekend when we came across an editorial issued by the Wall Street Journal on May 7, 1970, as America was becoming embroiled in the debate over President Nixon’s decision to launch an incursion into Cambodia.

In 1970, Nixon’s aim was to attack the Communists who were using the Cambodian jungles — and its ports and even its ordinary highways — as a base whence to attack American GIs and South Vietnamese forces in Vietnam. His attack was long overdue, in the opinion of many of our officers and GIs in Vietnam. Mr. Bush hasn’t — at least not yet — ordered an incursion into either Iran or Syria. On the contrary, the administration is wording its expressions of intent carefully, suggesting that whatever action it takes will take place inside Iraq.

Yet history suggests it would be wise to discount such talk. In the case of Cambodia in the spring of 1970, the administration was denying plans to invade Cambodia and denying that any incursions were taking place, even as South Vietnamese units were secretly operating — and fighting — inside Cambodia, entering from Chau Doc province in the northern part of the Mekong Delta. The big incursion that Nixon finally ordered was enormously successful in destroying huge amounts of enemy ammunition and supplies, not to mention enemy soldiers.

In 1970, the Journal remarked on the irony of what it called “the renewed concern, notably among liberals, about the enormous power of the Presidency.” The irony, it said, “lies in the fact that many of those souls had a good deal to do with the expansion of that power,” and its editorial traced the point back to the 1930s and World War II, and it also pointed out that the roots of the expansion of presidential power lie deep in the Constitution. It had put its finger on an important inversion in our political debate in the years since World War II.

This inversion has held for more than a generation now, never more so than today, as the Democrats get set to test presidential power in a way we hadn’t seen when the Republicans were running both the first and second branches. The themes back in 1970 were eerily similar. The New York Times was pressing for an end to the war, egging on Congress to use “its constitutional checks over the war-making powers of the president.” Today the Times is against the surge and wants Congress to pass “a set of bipartisan resolutions spelling out the broad policy directions Congress expects the president to pursue on Iraq.”

We’re not against the president and the Congress working out their differences in a political process, but our view inclines to the executive. Once Congress has granted the president broad war-making authority, as it did after September 11 and in resolutions on Iraq, it has its work cut out for it in trying to reverse course. We don’t say it can’t be done. But in Indochina, it took the Congress five years to assert itself – and then it made a terrible blunder, insisting on a retreat just when our military and allies had stabilized Vietnam and offered the Vietnamese a chance for democracy if they wanted it.

In a fell swoop, Congress cut off aid to Vietnam, precipitating the retreat from the Central Highlands and the communist conquest that followed. It’s that catastrophe that also deserves to be thought of with particular care today. The killing fields and re-education camps the Communists established in Vietnam and Cambodia dwarf the violence we’re seeing in Iraq today. After 1975, honest leftists were appalled at what they had helped precipitate. And it is well to remember that the Soviet Union, headwaters of much, though not all, of the evil, is history. And China, not to mention Vietnam itself, is eager to be part of our prosperity. So if we are starting to sense echoes of 1970, there is more than the struggle between the two branches of government about which to think.