MEXICO CITY  Mexico’s economy is being dragged down by the recession to the north. American addicts have turned Mexico into a drug superhighway, and its police and soldiers are under assault from American guns. Nafta promised 15 years ago that Mexican trucks would be allowed on American roads, but Congress said they were unsafe.

United States-Mexican relations are in the midst of what can be described as a neighborly feud, one that stretches along a lengthy shared fence. That border fence, which has become a wall in some places, is another irritant.

Secretary of State Hillary Rodham Clinton arrives in Mexico on Wednesday for what will be the first in a parade of visits by top administration officials, including President Obama himself next month, to try to head off a major foreign policy crisis close to home. They will find a country mired in a deepening slump, miffed by signs of protectionism in its largest trading partner, and torn apart by a drug war for which many in Mexico blame customers in the United States.

There is plenty of angst on the other side as well. Many American communities are worried about drug violence spilling over the border, and about Mexican immigrants taking scarce jobs. That is forcing the Obama administration, already managing two wars and a deep recession, to fashion a new Mexico policy earlier than it might have wished.