The Republican delegates seem to be looking for an unconventional candidate for the United States presidency. For this reason, I believe Mr Donald Trump, the controversial and leading Republican candidate, will be nominated ("Can Donald Trump still be stopped?"; March 25).

Many Americans, especially the middle- and lower-income groups, perceive that globalisation and free trade have led to job losses and widened income inequality in the US. Liberal immigration policies have created tremendous social problems, and the increased number of terrorist attacks globally has caused xenophobic sentiments to prevail.

The resulting unhappiness and frustration have led to calls for changes to safeguard their interests.

Although Mr Trump is deemed to be "politically incorrect" in his rhetoric, his approach enables him to strategically capitalise on these sentiments to advance his political career.

It is questionable if his immigration policies, such as building a "Mexican wall" and stopping Muslims from entering the US, are feasible. Nevertheless, his increased popularity signifies that Americans are subtly moving towards protectionism and inward-looking policies. The country may not continue to be the policeman of the world.

For decades, Singapore has been fortunate and benefited from the US' world leadership economically and politically.

We must be prepared to enter a new world where different regional powers will emerge and rule. These regional powers are the ones that will shape our political and economic viability in the future.

Paul Yong Teck Chong