After months of wrangling on Capitol Hill, the Senate today is expected to deliver President Obama a decisive political win and approve the New START arms-reduction treaty with Russia.

Treaty supporters are now confident they have more than the 67 votes required for approval despite lingering concerns among some Republicans that the accord could hamstring missile defense efforts or otherwise hurt the United States' strategic posture.

Foreign Relations Chairman John Kerry, D-Mass., who has shepherded the treaty through the Senate this year, said Tuesday he believes the vote will take place by early this afternoon, at the latest.

With the clock ticking down on the lame-duck session, Obama, Vice President Joe Biden, and other top administration officials stepped up their lobbying efforts in the last several days to push senators to approve New START, which the administration considers a top legislative priority for this year.

Their efforts, which included phone calls and closed-door meetings on Capitol Hill, seem to have paid off, as the list of Republican senators backing ratification of the treaty continued to grow early this week.