As talks between the beleaguered investment bank Lehman Brothers and Korea Development Bank crumbled yesterday, sending the bank’s shares tumbling 45% to their lowest level in more than 10 years, a new report by the Council on Foreign Relations highlights the role of foreign countries in propping up American assets.

Foreign government investments in American companies give these countries leverage over U.S. policies and limit America’s influence in the world, the report, published yesterday by a fellow for geoeconomics, Brad Setser, finds. While America has run a deficit for some 25 years, the current account deficit is historically large — it is twice the size, relative to gross domestic product, as it was in the 1980s. In addition, the rise in the deficit coincides with an increase in dollar surpluses in emerging economies such as China, which boasted the world’s largest current account surplus of $370 billion.

The $30 billion in new capital that American banks and broker-dealers raised from sovereign wealth funds in China, Singapore, and the Gulf states in just December and January is equal to the largest loan the IMF extended to any emerging economy.

“The United States’ main sources of financing are not allies,” Mr. Setser writes in the report. “Without financing from China, Russia, and the Gulf states, the dollar would fall sharply, U.S. interest rates would rise, and the U.S. government would find it far more difficult to sustain its global role at an acceptable domestic cost.”

The longer America relies on foreign central banks — which play a far larger role than the more widely known sovereign wealth funds, Mr. Setser said — the greater the risk that America’s dependence on external credit will constrain government policies.

Among Mr. Setser’s recommendations for remedying the situation is to consult more with allies who hold dollars, to improve exchange rate adjustments with foreign currencies so there is not as much motivation to hold foreign wealth in dollars, and to reduce America’s dependence on oil. Indeed, he suggests that America should push oil-exporting countries to use surplus revenue to pay out an oil dividend to citizens, rather than build up assets in sovereign wealth funds.

“The United States has run a current account deficit for some time. But never in the past has the growth in the foreign assets of other governments been so central to the financing of such a large deficit,” Mr. Setser concluded. “Reducing the United States’ current reliance on foreign governments to finance its deficit should be an important priority for the next president.”