"If people believe there's an imaginary river out there . . .

 . . .you don't tell them there's no river there.  You build an imaginary bridge over the imaginary river."

Who said that to whom?

It's from a San Francisco Chronicle book review of Rick Perlstein's The Invisible Bridge.

Image:  Invisible Bridge Over Invisible River

I'm just stalling and using up space so you can't peek to find the answer.   Reviewer Kevin Canfield explains the bridge in the book's title:

"Reagan's rhetorical bridge - the one that connected him with millions of likeminded voters, and later delivered him to the White House - was built on a foundation of uncompromising patriotism and smoldering resentment. It was a message that aggrieved conservatives (and, curiously, more than a few Democrats) found irresistible."

The New York Times reviewer, Frank Rich, explained it this way:

The key to Reagan’s political success, in Perlstein’s telling, was that he recognized what many Republicans did not — that Americans craved “a liturgy of absolution” and “an almost official cult of optimism” postulating “the belief that America could do no wrong” or “that if America did it, it was by definition not wrong.” That’s why Reagan stubbornly insisted on minimizing the crimes of Watergate even though polls suggested he might be punished for it and even after most of his ideological soul mates jumped ship. That’s why Reagan never stopped insisting that we came home from our humiliating defeat in Vietnam “as winners.” He propped up such illusions by ignoring facts or inventing them. But the will of his listeners to believe — and his gift for making them feel good in his presence — conquered all.

As you can tell, it's a book that people will like or hate depending on their political beliefs.  The SF Chronicle liked it.  So did the New York Times.

Ariel Gonzales' review in the Miami Herald, though, is titled:

"Liberal bias permeates Rick Perlstein’s time capsule of the pre-Reagan era"

But the review itself seems to have more respect for Perlstein than does the title:

But the camera is brutally honest and unforgiving in Perlstein’s hands. Expect no balance from this author, who never attempts to hide his liberal bias.
Regardless of your party affiliation, you may still enjoy his observations, which are often revealing and insightful.  .  .
If you hold Reagan in semi-divine status, however, this book is not for you. While Perlstein admires his “gift” for reducing complex problems to easily digestible partisan soundbites, he regards Reagan as a divider — a much more genial character than Nixon, yet just as culpable for widening ideological fault ines.[sic]

OK, who told whom to build an imaginary bridge?

Perlstein says it was Nikita Khrushchev to Richard Nixon.