During the campaign, it was "hope," and "yes, we can." Now, as US President Barack Obama is shifting from counting electoral votes to carbon emissions, he has a new catch phrase: "No single nation can meet the challenges of our time alone."
His underlying meaning: We need your help - and not in a patronizing way.
As the sole superpower since the collapse of the Soviet Union, the US is realizing that it can't tackle all the issues facing the world today alone. And as the largest developing country in the world, and one of the only nations that has not been devastated by the global financial crisis, China is more and more the one country the US looks to for assistance on major international and financial issues.
Indeed, as Obama prepares for a visit to China next month, he will need to work with China on issues as varied as financing America's growing national debt, supporting its decreasing international trade, and fighting terrorism. Perhaps most importantly, the US is widely expected to ask for Chinese help on the problem of climate change, one of Obama's top priorities.
But while China and the US have had much success in their cooperation - most notably during the so-called Strategic and Economic Dialogue (SED) talks in Washington earlier this year - climate change has thus far proved to be the toughest nut to crack.
Developed countries and developing countries still disagree over the best way to tackle global warming. Developed countries are demanding developing ones set binding targets on carbon emissions. But developing countries argue that the wealthier developed countries are responsible for most previous emissions and therefore should also be responsible for the sharpest emissions cuts and provide financial and technological support.
With December's global climate change summit in Copenhagen fast approaching, the possibility that it may not produce a binding treaty is growing. But Obama's visit to China presents a golden opportunity for the US and China to bridge their gap on global warming, and help push other countries to follow suit.
Obama's commitment to work with the rest of the world to solve problems bodes well for his trip to China.
For years after the formal establishment of diplomatic relations between China and the US, and particularly since the early 1990s, US Presidents have been perceived by the Chinese as lecturing the country on human rights and blaming China for its huge trade deficits each time they are here.
But now, for the first time in US history, an American President appears willing to listen to the voices of the other nations, including China. In fact, Obama has allocated more time to stay here (three nights, four days) than to two of America’s closest allies – Japan and South Korea - combined (two nights, four days).
There are other good signs.
Obama has appointed a Republican governor to serve as US ambassador to China, who is fluent in Mandarin and who has a commanding knowledge about the country. In addition, Obama appears to have developed a strong personal relationship with President Hu Jintao. This trip will be the fourth time he and President Hu will have met with each other this year - far more than their predecessors met. They have also spoken on the phone five times so far.
Still, nothing should be taken for granted. This is, after all, just the first state visit either leader has paid to the other, and some experts have tried to downplay expectations for the trip. But as President Obama said in a recent speech in Miami, Florida, "We are just getting started."