In politics (and particularly in international politics), soft power is the ability to co-opt rather than coerce (in contrast with hard power). It involves shaping the preferences of others through appeal and attraction. Soft power is non-coercive, using culture, political values, and foreign policies to enact change. In 2012, Joseph Nye of Harvard University explained that with soft power, "the best propaganda is not propaganda", further explaining that during the Information Age, "credibility is the scarcest resource".

Nye popularised the term in his 1990 book, Bound to Lead: The Changing Nature of American Power.

In this book he wrote: "when one country gets other countries to want what it wants might be called co-optive or soft power in contrast with the hard or command power of ordering others to do what it wants". He further developed the concept in his 2004 book, Soft Power: The Means to Success in World Politics.

The Oxford English Dictionary records the phrase "soft power" (meaning "power (of a nation, state, alliance, etc.) deriving from economic and cultural influence, rather than coercion or military strength") from 1985. The influential international relations scholar Joseph Nye popularized the concept of "soft power" in the late 1980s. For Nye, power is the ability to influence the behavior of others to get the outcomes you want. There are several ways one can achieve this: one can coerce others with threats; one can induce them with payments; or one can attract and co-opt them to want what one wants. This soft power – getting others to want the outcomes one wants – co-opts people rather than coerces them.

Soft power contrasts with "hard power" – the use of coercion and payment. Soft power can be wielded not just by states but also by all actors in international politics, such as NGOs or international institutions. It is also considered by some an example of the "second face of power" that indirectly allows one to obtain the outcomes one wants. A country's soft power, according to Nye, rests on three resources: "its culture (in places where it is attractive to others), its political values (when it lives up to them at home and abroad), and its foreign policies (when others see them as legitimate and having moral authority)."

"A country may obtain the outcomes it wants in world politics because other countries – admiring its values, emulating its example, aspiring to its level of prosperity and openness – want to follow it. In this sense, it is also important to set the agenda and attract others in world politics, and not only to force them to change by threatening military force or economic sanctions. This soft power – getting others to want the outcomes that you want – co-opts people rather than coerces them."

Soft power resources are the assets that produce attraction, which often leads to acquiescence. Nye asserts that, "Seduction is always more effective than coercion, and many values like democracy, human rights, and individual opportunities are deeply seductive." Angelo Codevilla observed that an often overlooked essential aspect of soft power is that different parts of populations are attracted or repelled by different things, ideas, images, or prospects. Soft power is hampered when policies, culture, or values repel others instead of attracting them.

In his book, Nye argues that soft power is a more difficult instrument for governments to wield than hard power for two reasons: many of its critical resources are outside the control of governments, and soft power tends to "work indirectly by shaping the environment for policy, and sometimes takes years to produce the desired outcomes." The book identifies three broad categories of soft power: "culture", "political values", and "policies."