The US is a nation of immigrants. Except for a small number of native Americans, everyone is originally from somewhere else, and even recent immigrants can rise to top economic and political roles. President Franklin Roosevelt once famously addressed the Daughters of the American Revolution - a group that prided itself on the early arrival of its ancestors - as “fellow immigrants.”

In recent years, however, US politics has had a strong anti-immigration slant, and the issue played an important role in the Republican Party’s presidential nomination battle in 2012. But Barack Obama’s re-election demonstrated the electoral power of Latino voters, who rejected Republican presidential candidate Mitt Romney by a 3-1 majority, as did Asian-Americans. As a result, several prominent Republican politicians are now urging their party to reconsider its anti-immigration policies, and plans for immigration reform will be on the agenda at the beginning of Obama’s second term. Successful reform will be an important step in preventing the decline of American power.

Fears about the impact of immigration on national values and on a coherent sense of American identity are not new. The 19th century “Know Nothing” movement was built on opposition to immigrants, particularly the Irish. Chinese were singled out for exclusion from 1882 onward and, with the more restrictive Immigration Act of 1924, immigration in general slowed for the next four decades.

During the 20th century, the US recorded its highest percentage of foreign-born residents, 14.7 percent, in 1910. A century later, according to the 2010 census, 13 percent of the American population is foreign born. But, despite being a nation of immigrants, more Americans are sceptical about immigration than are sympathetic to it. Various opinion polls show either a plurality or a majority favouring less immigration. The recession exacerbated such views: in 2009, one-half of the US public favoured allowing fewer immigrants, up from 39 percent in 2008.

Both the number of immigrants and their origin have caused concerns about immigration’s effects on US culture. Demographers portray a country in 2050 in which non-Hispanic whites will be only a slim majority. Hispanics will comprise 25 percent of the population, with African- and Asian-Americans making up 14 percent and 8 percent.

While too rapid a rate of immigration can cause social problems, over the long-term, immigration strengthens US power. It is estimated that at least 83 countries and territories currently have fertility rates that are below the level needed to keep their population constant. Whereas most developed countries will experience a shortage of people as the century progresses, America is one of the few that may avoid demographic decline and maintain its share of world population.

Today, the US is the world’s third most populous country; 50 years from now it is still likely to be third (after only China and India). This is highly relevant to economic power: whereas nearly all other developed countries will face a growing burden of providing for the older generation, immigration could help to attenuate the policy problem for the US.

In addition, though studies suggest that the short-term economic benefits of immigration are relatively small, and that unskilled workers may suffer from competition, skilled immigrants can be important to particular sectors - and to long-term growth. Equally important are immigration’s benefits for America’s soft power. The fact that people want to come to the US enhances its appeal, and immigrants’ upward mobility is attractive to people in other countries. Moreover, connections between immigrants and their families and friends back home help to convey accurate and positive information about the US.

Likewise, because the presence of many cultures creates avenues of connection with other countries, it helps to broaden Americans’ attitudes and views of the world in an era of globalisation. Rather than diluting hard and soft power, immigration enhances both. That is a view that Americans should take to heart. If Obama succeeds in enacting immigration reform in his second term, he will have gone a long way toward fulfilling his promise to maintain the strength of the US.

The writer is a university professor at Harvard University. This article has been reproduced from the Turkish newspaper, Today’s Zaman, with which TheNation has a content-sharing agreement.