The Obama administration plans to file a broad trade case at the World Trade Organization in Geneva on Monday accusing China of unfairly subsidizing its exports of autos and auto parts, a senior administration official said late Sunday, in a move with clear political implications for the presidential elections less than two months away.

The W.T.O. case accuses China of providing at least $1 billion worth of subsidies from 2009 to 2011 for exports of autos and auto parts. While China exports virtually no fully assembled cars to the United States, it has rapidly expanded exports to developing countries, and those exports compete to some extent with cars exported or designed in the United States.

President Obama plans to announce the move on Monday during a visit to Ohio, one of the most important of the battleground states and a place where the president is trying to capitalize on his bailout of the auto industry. A poll by NBC News, The Wall Street Journal and Marist College last week showed Mr. Obama building a significant lead in Ohio.

The upper Midwestern states have emerged as a key battleground in the presidential election, particularly Ohio, which has rivaled Florida in recent presidential elections as the most hard-fought state of all. Ohio is also the hub of the American auto parts industry, which has suffered heavily from job losses that have coincided with surging imports of auto parts from China.