US Senator Chris Dodd, a key ally of President Barack Obama, has announced that he will not seek re-election in November.

美国参议员克里斯·多德，奥巴马总统一位关键伙伴，声称自己11月份不会寻求连任。

Senator Dodd was expected to face a tough re-election battle

In a statement, Mr Obama thanked him for his service and said his leadership on Capitol Hill美国国会山 would be missed.

Mr Dodd's move follows the decision by fellow Democratic Senator Byron Dorgan not to stand again.

The Democrats¹ have 60 Senate votes, just enough to overcome Republican efforts to block legislation.

The balance of power could change after November's elections, when a third of the 100 Senate seats will be contested竞争，争辩.

Voters will also elect all 435 members of the House of Representatives.

Senator Dodd, who chairs the Senate banking² committee, made the announcement that he would not be seeking re-election for a sixth term outside his home in East Haddam, in the state of Connecticut.

"I have been a Connecticut senator for 30 years. I'm very proud of the job I've done and the results delivered," Mr Dodd told reporters.

"But none of us is irreplaceable. None of us are indispensable不可缺少的. And those who think otherwise are dangerous," he added.

"In the long sweep of American history there are moments for each elected public official to step aside避开，让开 and let someone else step up. This is my moment to step aside."