As 2006 begins, an American looking out at the world from the geographic center of the United States, just west of Lebanon, Kan., would see five nations critical to the security of America — Canada, Mexico, Japan, Australia and Britain.

Gone are the Cold War days when the United States, no matter who was in power, sought to win over every nation in the rivalry with the Soviet Union.

Today, America seems to be more selective and to focus on those nations that directly affect U.S. national interests.

To the north, Americans must have friendly neighbors along the 5,000-mile border with Canada and, to the south, along the 2,000-mile border with Mexico; both frontiers are largely undefended and could be highways for terrorists. Yet relations between Washington and Ottawa and Mexico City today are sour, maybe even bitter, by any measure.

To the west, across the Pacific, are Japan and Australia and, to the east, across the Atlantic, is Britain. America's alliance with each seems strong but may be rooted more in personal relations between President Bush and prime ministers Junichiro Koizumi of Japan, John Howard of Australia and Tony Blair of Britain rather than in deep-seated national interests.

Each has generated political opposition at home for being pro-American. Koizumi has said he will step down next fall. Howard has taken much heat from Australians who want assurances they will not be dragged into a war between China and the United States. Blair's popularity has plummeted, and his days in office may be numbered.

These island nations are essential to U.S. security, as they sit off the Eurasian continent that is home for three quarters of the human race and most of the world's industry and wealth. In Eurasia are the only military powers — China, Russia, North Korea — that could threaten the United States.

The Islamic swath from Morocco to the southern Philippines is the source of most anti-American terrorists.

These three alliances are invaluable in international politics and are indispensable as military bases, whether temporary as in Australia or long-term in Japan and Britain. Britain especially plays a vital role in the shadowy world of intelligence.

All is not well, however, with the two allies closest to home. Canada, the leading trade partner of the United States, has long been ambivalent about the dominating culture of the colossus to the south. Today, says the Economist magazine, Canadians have become "grumpily anti-American," due largely to a distaste for President Bush and the war in Iraq.

A spat between the U.S. ambassador to Ottawa, David Wilkins, and Prime Minister Paul Martin has aggravated the ill feelings. Martin has been critical of U.S. trade and environmental policies as he campaigned in an election scheduled for Jan. 23.

Ambassador Wilkins responded: "Just think about this," he was quoted in the New York Times, "What if one of your best friends criticized you directly and indirectly almost relentlessly? What if that friend's agenda was to highlight your perceived flaws while avoiding mentioning your successes?"

In Mexico, the second-largest trading partner of the United States, there has long been resentment of the wealth of Americans. That has been aggravated by recent disputes over trade and especially the issue of Mexican immigrants, legal and illegal, to the United States.

After the U.S. House of Representatives approved a bill that calls for a 700-mile fence along the U.S.-Mexican border, many Mexicans called it a "Berlin Wall." President Vicente Fox said: "We do not understand this step toward building walls" and "to sending more police and soldiers to the border."

When President Bush came into office in January 2001, high on his agenda was fostering new relations with Canada and Mexico. His first foreign trip, in February, was to Mexico. "I intended it to be that way," he said, and spoke glowingly of a partnership to "improve the lives of citizens in both countries."

Two months later, the president went to Canada to a summit meeting with Canadian and Mexican leaders. "Together," he said as he departed from the White House, "we will put forward an agenda to strengthen our democracies, to tackle common challenges and we will seek to expand our prosperity by expanding our trade."

Brave words that, like a lot of other things, faded into neglect after the terrorist assaults of 9/11, the invasions of Iraq and Afghanistan, and the continuing antagonism between Israel and the Palestinians captured the administration's attention.

Honolulu-based Richard Halloran is a former New York Times correspondent in Asia.