Washington : Two big wins for Barack Obama at home and abroad — a historic health care bill and a new arms treaty with Russia — have injected sudden momentum into a presidency that had been looking beleaguered.

"What a week here," White House press secretary Robert Gibbs wrote on his twitter feed, as Obama concluded a new strategic arms reduction treaty in a call with Russian President Dmitry Medvedev on Friday.

Tough issues

In six days, two of the biggest projects of Obama's presidency came to fruition after months of painstaking work, transforming the image of an administration that had swung hard but failed to connect on big agenda items.

By Friday, Obama could savour the spectacle of the pundits he frequently decries, switching from a "this presidency is over" mantra, to hailing him as a conquering domestic president and a global statesmen.

The lofty expectations of a transformative presidency, which shackled Obama when he took office amid the deepest economic crisis in generations, look a little less hubristic, after his best week in the White House.

The president has already framed a narrative that he is a leader, who has delivered the change he promised, and will stick with tough issues to the end.

"It took patience. It took perseverance. But we never gave up," Obama said Friday, referring to tortuous negotiations with Russia. So will this renewed presidential swagger help Obama capture the momentum in a volatile election year and lead to progress on tricky foreign policy problems?

Global stage

The White House noted several times this week that foreign leaders congratulated Obama on his health care triumph. The image of a successful presidency is important, analysts said, and may enhance Obama's leverage on difficult issues like Iran's nuclear programme, non-proliferation and the Middle East.

"When a president is doing badly in the US, there is less reason to fear him abroad," said Julian Zelizer, a political historian at Princeton University.

As he piloted health care through the fractious Congress and concluded arms negotiations with Russia this week, Obama was also in the middle of a rare, and public test of wills with Israeli Prime Minister Benjamin Netanyahu.

That image of an engaged president mastering Washington politics while navigating a treacherous world may also change some minds about Obama's tenacity.

But while Obama may have enhanced his statesman's credentials, it seems unlikely his personality alone can shift the policy of US foes and allies.