Are Airport Demonstrations Useful?

Some I know have given up on political demonstrations, which is their right. 

When our politics change, it’s hard to assign credit. Did the massive demonstrations in Washington City gradually turn the American voters against the Vietnam War? Maybe. I was there, but I can’t prove anything. Did massive demonstrations against the second war against Iraq prevent the war? No. But they did help gradually turn public opinion around, which contributed to Obama’s primary defeat of Clinton. (Back then we prudently  nominated candidates the voters liked.)

At this moment there are huge crowds at airports protesting Minority President Trump's executive order banning entry to people from seven largely Moslem nations. Trump, a malignant narcissist, is trying to keep his loony pledge to ban Moslems in general.  So far the narcissist has quickly released everyone in our airports that his stooges have detained. I’d say that that has happened in part because of the airport protests around the country—and also because even spineless politicians like Sen. Schumer have denounced the bans and because  lawsuits have been filed and because a few Republicans, braver than the gutless Schumer,  have spoken up and so on. Many things contribute, and protests do matter at times, apparently.