During the Vietnam War, President Lyndon B. Johnson chose to spend on guns and butter, spurring a debilitating period of runaway inflation. Today, given President Bush's predilection for big tax cuts and large defense budget increases, it is increasingly an era of just guns.

The $379.9 billion defense budget proposed by the Bush administration for the fiscal year that begins in October is 16 percent more than all other discretionary spending combined, excluding spending on homeland defense. And that does not include the $1.6 billion a month the United States is spending to fight the war on terrorism or the cost of a war and occupation in Iraq, which could be more than $50 billion.

Even without those costs, $379.9 billion is roughly 10 times what Britain or France spend on defense, or twice as much as the other 18 NATO countries combined. Yet Republicans and Democrats on the pro-defense House Armed Services Committee told Secretary of Defense Donald H. Rumsfeld that the Pentagon's billion-dollar-a-day budget is $43 billion to $100 billion short -- insufficient to maintain the nation's current conventional forces and modernize its aging ships, aircraft and vehicles, let alone build a missile defense network and keep the United States ahead of its adversaries by investing in new technologies.

With the budget deficit having ballooned to a projected $307 billion next fiscal year, not counting war costs, the administration's military ambitions are already cutting into other national priorities, such as education, health, welfare and the environment.

But in the post-Sept. 11 climate, that guns vs. butter debate seems largely to have been resolved in favor of guns. Now the issue on Capitol Hill is whether the country can buy both 20th-century guns and 21st-century guns.

Rep. Duncan Hunter (R-Calif.), the House Armed Services Committee chairman, believes defense spending needs to be $43 billion a year higher. The current budget, he warned Rumsfeld at a recent committee hearing, is shortchanging the present by focusing on the future.

The Pentagon has already cut one-third of the nation's 90-plane B-1 bomber fleet to modernize the remaining two-thirds, Hunter complained.

"We continue to cut into the very foundation of our conventional combat power solely to free up funds for other needed initiatives," Hunter said. "Simply put, Mr. Secretary, we should not be forced to incur such near-term risk in terms of diminished combat capability in order to invest in the future solely because we have not properly resourced the defense budget."

Rep. Ike Skelton (Mo.), the committee's ranking Democrat, complained that the Navy's 301-ship fleet would shrink under the new budget to 291 ships, the lowest level since 1916, despite the investment of $12.5 billion for building seven new ships.

"I know that our ships have far greater capabilities now," Skelton said, "but the geography of the oceans is unchanged."

Rumsfeld acknowledged that there was plenty of "bad news" in the administration's proposed defense budget, even with its $16.9 billion increase over a year ago, by far the biggest in dollar terms in the overall federal budget.

There is not enough money to reduce the average age of the military's tactical aircraft or purchase enough specialty assets, such as JSTARS radar aircraft, to resolve chronic shortages. And beyond the B-1, upgrades of numerous other Cold War-era weapons -- such as the M1A1 Abrams tank -- have been discontinued.

Rumsfeld has a proposal for balancing the demands of funding current military personnel needs, operations and maintenance, while sustaining modernization and transformation: more money.

The budgets his Pentagon is proposing assume a steady $20 billion increase in defense spending every year for the next six years -- a surge that would come on top of six straight years of real increases in defense spending. It would push overall annual spending on national defense past half a trillion dollars.

Since Sept. 11, 2001, these increases have faced very little debate, and almost no opposition, in Congress. But that is almost certain to change, in the face of cuts across the rest of the budget, or when the bill comes in for ongoing military operations in Afghanistan and the likely war in Iraq, or if economic recovery is slow in coming.

In many ways, Sept. 11, 2001, has postponed a full national debate on the implications of military transformation and the Bush administration's ambition of keeping the U.S. armed forces second to none for decades to come.

Retired Army Lt. Col. Andrew F. Krepinevich Jr., director of the Center for Strategic and Budgetary Assessments, said there will most likely be two large strains on the defense budget. One could come when Congress tries to recoup some of the money it has spent fighting wars by cutting defense increases down the road, he said. The other could come from "budget deficits, an administration trying to hold down domestic discretionary spending and, at the end of the decade, the baby boomers starting to retire."

"Every 20 years, you get a major [defense] increase, followed by a gradual decline," he said. "The 20-year on-schedule buildup has come along, but if history is any guide, it's going to level off, and it always levels off before the military wants."