The United States may be in a weary mood as the strains of being the top global leader take their toll, but the country will eventually rally again, Prime Minister Lee Hsien Loong said.
In an interview with Washington-based political news magazine Politico, Mr Lee said the US "has been through these ups and downs before".
"After Vietnam, you had a period of withdrawal and being tired of the sacrifices and the pain and difficulties of the world, but you bounced back and I am quite sure you will bounce back this time," he said, referring to the US involvement in the Vietnam war in the 1960s and 1970s.
Mr Lee also noted that while American leaders have to watch "issues all over the world", their attention is not equally spread in all directions.
He urged a greater focus on Asia, where unfolding geopolitical trends such as China's rise and Asia's growing interconnectedness could affect the US' interests in the region unless it plays a more active role.
The interview, which spanned a range of foreign policy issues from the territorial tensions in the South China Sea to the effect of the Ukraine crisis on Asia, was conducted last week during Mr Lee's week-long trip to the US, and published on Tuesday.
Mr Lee had visited Washington DC and New York, where he met with top US political leaders to drive home the importance of US participation in and ratification of the Trans-Pacific Partnership, a free trade pact covering 12 nations including the US, Japan and Singapore.
In the Politico interview, Mr Lee also highlighted that it was important for Japan to remain in the TPP "because they are a key strategic partner of the US in Asia".
New Zealand Prime Minister John Key had suggested last month that Japan be cut out of the TPP negotiations if it refuses to agree to open its markets to more imports of farm products, one of the remaining sticking points of the trade talks.
But Mr Lee said the TPP is a key way for the US to maintain its ties with Japan.
"You have a security alliance with them. Your ties with China now, probably the volume is greater, but you have to maintain that link with Japan," he said.
"And if you leave them out from the TPP or drop them, having invited them to negotiate, I think that is very bad."