In the mid-1980s, Japanese and other foreign investors were snapping up high-profile business assets in the United States with such frequency as to bring on a bout of national hand-wringing.

Alarmists saw the acquisitions as threats to U.S. technological and economic security, if not sovereignty. In the end, though, they represented little more than a blow to national pride.

Now, with Mitsubishi Heavy Industries' bid for Westinghouse Electric Co., the nation's largest builder of nuclear plants, following on the heels of China's bid for Unocal, the ninth-largest oil producer, concerns about U.S. economic security and even national security are rife once more.

Is it deja vu all over again? Some economists think so.

Even though the industry in foreign cross hairs is energy at a time when oil prices are soaring, "My own feeling is that the concerns today are even sillier" than they were in the 1980s, when Japan set off a national furor that hit a high-point with Mitsubishi Corp.'s investment in Rockefeller Center, said Edward M. Graham, a senior research fellow at the Institute for International Economics.

Graham, co-author of a 1980s book titled "Foreign Direct Investment in the United States," said there were some legitimate concerns raised about a few of Japan's technology purchases two decades ago.

He also said that there may be some need for a federal review of national security issues related to the acquisition of a U.S.-based nuclear concern, even though Westinghouse itself is already owned by a foreign company, British Nuclear Fuels.

But the mere acquisition of energy assets by Japanese companies, China or others should neither surprise nor worry federal policymakers and politicians, many of whom already are sounding alarms, he and several other economists said yesterday.

"I think the ownership of these companies [Westinghouse and Unocal] are not terribly important," said Lester Lave, an economist at Carnegie Mellon University's Tepper School of Business.

"Suppose this part of Westinghouse was sold to Mitsubishi and five years from now they said they wouldn't participate in constructing nuclear plants in the United States? You'd have to say 'So what?' " because there are other contractors, in France, Germany and elsewhere who'd gladly do the work, he said.

As for China seeking an oil company, "The world oil market is about as fungible a market as there is," with supplies moving readily in response to demand, Lave said.

Graham said a Chinese purchase of a domestic oil company might even be better for domestic consumers than a rival bid from a U.S. company, such as the one Chevron has made.

Chevron might have more of an interest in holding down production, "because its bread is buttered by high oil prices," whereas "China is desperately short of oil and might be more inclined to expand'' production, which could soften world-market prices, he said.

Similarly, "Japan is a big nuclear generation user, so it's not illogical for them to look for nuclear technology," said Fariborz Ghadhar, director of Penn State University's Center for Global Business Studies.

Moreover, by protecting U.S.-based energy assets from foreign takeover, economists said the United States would be sending a risky signal to Russia, Mexico, Venezuela and other countries weighing whether to permit increased U.S. investment in their own oil reserves.

Rhetoric in Congress and elsewhere about foreign purchases of U.S.-based energy assets "reminds me exactly of our paranoia about the Japanese in the late 1970s and 1980s," Ghadhar said.

Besides, he noted, the Japanese "ended up overpaying for all of those things anyway." He speculated that the same might happen with energy.

Ghadhar doesn't think oil prices that have ranged from $50 to more than $60 a barrel in recent months are sustainable over the long term. Anything that would burst the oil bubble also would dampen values for competing energy sources.

Economists also noted that, in addition to strategic or economic considerations, the spate of foreign interest in U.S. energy assets is driven by many of the same factors that have sporadically fueled foreign investment in domestic companies and real estate: The foreign investors simply have the money.

Record U.S. government budget and trade deficits, combined with high savings rates abroad, have left many countries flush with cash, particularly U.S. dollars, that have to be invested somewhere.

That much of it is ending up in the United states, either through direct purchases of U.S. Treasury securities or domestic companies and plants, is no surprise. The United States is still the world's largest economy and a desirable place to invest.

But if alarmists are concerned about the trend that gives foreigners a greater claim on U.S. assets, there is one thing that can be done, CMU's Lave said. "If you want to be concerned about selling things off [to foreign investors], the first thing you have to do is get rid of the deficits."