"Do Intelligent Arguments Make A Difference?" Ctd

A reader writes:

This thread reminds me of a quote by Max Planck that I found in Thomas Kuhn's "The Structure of Scientific Revolutions":  

A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.

Ambreen Ali responds to DiA's inability to "think of an instance where voters on any side have been persuaded by a reasoned opposition on any issue":

Here's one: the civil rights movement.

In addition to boycotts and sit-ins, leaders such as Martin Luther King, Jr., debated opponents publicly to persuade Americans to back the cause. Historian Kevern Verney writes about this in his book, "The Debate on Black Civil Rights in America":

[King's] intelligent and articulate responses in media interviews contrasted painfully with the uncouth and intemperate outbursts of some of his best-known segregationist opponents. In print he lucidly and persuasively explained the intellectual basis of his beliefs and showed these were rooted in the core values of western philosophy, demonstrating both his erudition and the moral justification of the civil rights cause.

The movement's iconic marches and sit-ins are remembered most today, but ideas and arguments formed its basis.

To be fair, our colleague does credit the "gravitational pull of mounting social change" for helping causes such as gay marriage. But we feel this misses the point: That amorphous gravitational pull comes about only after years, and sometimes decades, of activists making the case for social change.