Marekani ilianza karne ya 21 ikiwa ni nguvu kuu ya dunia isiyo na mpinzani. Kwa kiwango cha kimataifa, Marekani iligusa kila mtu kwa njia tofauti: kupitia Hollywood, teknolojia ya Marekani - Microsoft, chakula cha haraka - McDonald's, vinywaji vyenye gesi - Coca Cola, vyombo vya habari vya televisheni - CNN, vyombo vya habari vilivyochapishwa - New York Times, International Herald Tribune, mtandao - Google, Yahoo, na fedha - Wall Street. Kwa zaidi ya karne moja, Marekani imetawala siasa, uchumi, sera za nje na utandawazi.

The USA began the 21st century as the world’s unrivalled superpower. Globally the USA touched everyone in different ways, through Hollywood, US technology - Microsoft, fast food - MacDonald’s, fizzy drinks - Coca Cola, news media - CNN, print media - the New York Times, International Herald Tribune, internet - Google, Yahoo, and finance - Wall Street. For over a century the United States of America has dominated politics, economics, foreign policy and globalisation.

Wakati George W. Bush alipokuwa rais wa Marekani mwaka 2001, Wananeoconservatives, ambao walijaza serikali yake, walizungumzia haja ya kuonyesha nguvu ya Marekani hadi karne ijayo. Katika "mradi wao kwa karne ya 21," walizungumzia ahadi za kimataifa, sheria za kimataifa na mikataba ya kimataifa, wakisema kwamba hizo zinazuia ubabe wa Marekani, na kwamba Marekani haihitaji hizo kwa kuwa ni nguvu kuu ya dunia.