By Richard Galpin
BBC News, Moscow
Mr Medvedev has helped drive a more positive relationship with the US
The formal announcement of an agreement on a major arms reduction treaty with the United States will help boost the standing of Russia's President Dmitri Medvedev who has made the reset of relations with Washington a cornerstone of the country's foreign policy.
It is one of very few achievements which he can genuinely claim as his own after two years in power under the shadow of his mentor, the former President and now Prime Minister Vladimir Putin.
Mr Medvedev has been in the driving seat in developing a much more positive relationship with the Americans and appears to be on good terms with President Barack Obama.
It has, however, taken much longer to reach this point than Presidents Medvedev and Obama had expected when they presented the outlines of a new Start treaty at their historic summit here in Moscow last July.
They wanted the deal to be completed by the end of last year when the existing treaty expired.
While the agreement is a symbolic shot in the arm for Mr Medvedev's anaemic presidency, experts here believe that from a purely military point of view, it is not that significant for Russia
The differences between the two sides proved to be more difficult to overcome than they'd predicted with disputes over monitoring, the sharing of sensitive military information and the United States' latest missile defence plans.
Prime Minister Vladimir Putin and Russia's military leaders have been particularly insistent that the plans for a missile shield be scaled down as part of any new treaty.
The military chiefs here argue that installing interceptor missiles in countries such as Romania would undermine the strategic nuclear balance between Russia and the United States.
At the moment it's not clear how this hurdle has been overcome, but telephone calls between the two presidents appear to have driven the process forward enabling an agreement to be reached.
"It is clear that Mr Putin is not very happy with this treaty," says defence expert Alexander Goltz.
While the agreement is a symbolic shot in the arm for Mr Medvedev's anaemic presidency, experts here believe that from a purely military point of view, it is not that significant for Russia.
In fact, in terms of the number of missiles, planes and submarines both sides will be able to keep to deliver nuclear warheads, it will not make any difference at all, as each country is allowed a total of 700.
"Russia will not cut anything," says Mr Goltz, "Russia only has 600 delivery vehicles."
And while Russia will have to cut the number of deployed nuclear warheads by almost a half, its nuclear arsenal is shrinking anyway because of the age of the weapons.
So the reduction suits Moscow as it means it will have to replace far fewer warheads while still maintaining parity with the United States.