"Acid, amnesty and abortion" are back. Or perhaps they never left. The phrase, which was used to tar the 1972 presidential candidacy of Democratic Sen. George McGovern, implied softness on illegal drugs, indulgence of Vietnam draft dodgers and endorsement of women's sexual freedom. (It originated, unbeknownst to McGovern, in an off-the-record comment by the man who became his temporary running mate, Thomas Eagleton.)

Acid isn't much in the news anymore, but shifting public opinion on marijuana - punctuated by its legalization in Colorado and Washington - has staked out new terrain on drugs. Amnesty no longer refers to draft evaders but to undocumented immigrants seeking legal status, an issue that may be growing even more contentious than its Vietnam-era antecedent. And abortion? Still here. After 40 years as a political wedge used by all sides, it has gained new prominence in the conservative agenda.

The trend toward marijuana legalization has been steady for more than two decades.

Now, a majority of Americans support legal marijuana - but not a majority of Republicans.

With two-thirds of millennials backing legalization, it won't be easy for conservatives to squeeze the wavy gravy back in the bottle.

On amnesty for undocumented immigrants, an overwhelming majority of Americans support a pathway to citizenship or legalization, with only 22 percent in a Public Religion Research Institute poll last month saying they support deportation.

Yet House Republicans recently voted essentially to deport even the most sympathetic undocumented immigrants - the "Dreamers" who came to the U.S. as children.

The anti-immigration hard-liners, supported in part by constituents who fear an emerging non-white majority, have seized control of the Republican debate.

Marco Rubio, who was instrumental in passing the Senate's comprehensive immigration reform, has retreated, saying the United States should now "wind down" Obama's Deferred Action for Childhood Arrivals.

Arizona Sen. John McCain has similarly surrendered. The party has allowed nativist Rep. Steve King of Iowa and his anti-immigration colleagues to set a toxic tone that could undermine the party among Asian and Hispanic voters for years.

On abortion, Republican legislatures and governors across southern and plains states have enacted laws to drive abortion clinics out of business, which may prove no more successful in the long run than more forthright efforts to undermine the right established in Roe v. Wade. Two federal courts recently blocked such laws in Alabama and Louisiana, and it's hard to see how the U.S. Supreme Court could counter those rulings without overturning Roe, among the most politically precarious moves the court's activist bloc could consider.

Even if the cultural terrain of drugs, amnesty and abortion looks familiar, the symbols and passions have shifted. Conservative alienation has supplanted the leftist version that damaged McGovern and his party in 1972.

The tea party variant isn't violent, but it's also getting pretty weird. It's hard to imagine a more defensive, insecure and borderline pathological political expression than "rolling coal," the conservative subculture in which drivers spend money to rig their trucks to befoul the air with dense black smoke.

Why? Because of environmentalists. Or whatever.

Likewise, a man arrested in Phoenix's international airport after parading with his AR-15 semi-automatic rifle noted that his high-caliber perambulation was "entirely political in nature." (At least he wasn't claiming self-defense.)

When political statements require terrifying fellow citizens over coffee and scrambling law enforcement officers it's well past time to check your political psychology.

After the debacle of the House immigration bill, in which successive waves of bad faith and bad politics cascaded over the House floor, Rep. Peter King of New York, a one-time conservative now viewed as a RINO, said, "Ted Cruz and a handful of Republicans have hijacked the party."

King is wrong, of course. The slow-motion hijacking began years before Cruz, a Republican from Texas, joined the Senate. Despite sporadic efforts to channel conservative energies in more fruitful directions, the takeover is arguably near completion.

The question is whether conservatives can reclaim their party and their cause, or whether they will soon be defined by a political manifesto that consists of blowing black smoke and scaring people in airports.

Francis Wilkinson is a columnist for Bloomberg View.