Although the Democrats tend to be more concerned about the non-proliferation agenda, their political leadership in the last few weeks has been sending consistent signals that the deal will not be in danger if they gain control of either or both Houses.

Two national opinion polls Monday showed Democrats held a double-digit advantage contradicting two surveys on Sunday that showed the Republicans closing the gap on Democrats. The Democrats hope that the unpopularity of President George W Bush, the anger at the failing war in Iraq, and the recent scandals involving Republican Congressmen, have “nationalised” the mid term elections that normally tend to be dominated by local politics.

The Republicans, in contrast, expect that the traditional advantages of incumbency in the U.S. Congress, and a structural majority in favour of the Republican Party in evidence since the early 1990s, might help fend off the Democratic challenge.