COLUMN LEFT : Ties Bind Meddlers to Murderers : U.S. policies in Cambodia and Peru help rather than hinder savage guerrilla movements.

A belated glimmer of light comes from Cambodia. Jolted into reality by the steady advance of the Khmer Rouge, the United States has at last withdrawn its recognition from the three-party coalition that is dominated by Pol Pot’s cadres. But on the other side of the world, in Peru, there is a simultaneous step into darkness. U.S. advisers are to help fight the drug war there--and the guerrillas of Sendero Luminoso.

Sendero, which has taken thousands of lives, announced its presence a decade ago by hanging dead dogs from lampposts. The Khmer Rouge, on their way to murdering a million people, regarded anyone who wore eyeglasses as a class enemy. The horror stories are all true. But they conjure up an image of alien forces that sprang from the earth overnight like some rare and malignant bloom. In fact, the two guerrilla armies have deep and tenacious roots, and the United States has done more to strengthen them than it would care to admit.

Sendero’s leader, Abimael Guzman, the “fourth sword of world revolution,” proposes to transplant to Peru the Maoism of China’s Cultural Revolution. The ideology of Pol Pot, who is still in control of the Khmer Rouge, has not changed an iota since the 1970s. (And anyone tempted to see Prince Norodom Sihanouk as the straight man of this act should look at a bizarre little book called “Charisma and Leadership,” which contains his rambling, admiring thoughts on such figures as Haile Selassie and Nicolae Ceausescu.)

Both organizations thrive on the misery of peoples abandoned by modern urban society. Both idealize flourishing ancient civilizations. Foreign invaders destroyed the Inca and Khmer empires; to add insult to injury, their descendants were then told that their great monuments had been “discovered” by Westerners--the ruins of Machu Picchu by the American Hiram Bingham in 1911, the temples of Angkor by the Frenchman Henri Mouhot in 1860. Jose Carlos Mariategui, a Peruvian Marxist much revered by the Senderistas, believed the Incas had developed a form of “agrarian communism.” The Khmer Rouge believe they incarnate a thwarted national dream and talk of making their final stand at the great temples of Angkor.

In countries as corrupted as Cambodia and Peru, anti-capitalist asceticism evidently has its appeal. Visitors to Cambodian refugee camps in Thailand report that rape, theft and violence are rife in areas run by Son Sann’s non-communist resistance, but not in the austere camps of the Khmer Rouge. And while most Peruvian jails recall scenes from the movie “Midnight Express,” the Sendero-run cellblocks are, by all accounts, spotless and highly disciplined.

In Peru, market-driven economic strategies have failed miserably. City and countryside are worlds apart. American pundits and the Lima elite saw the novelist Mario Vargas Llosa as Peru’s last, best hope. But his drive for the presidency went down in flames, despite--or perhaps because of--a multimillion-dollar U.S.-style campaign.

In Cambodia, the rule of Prince Sihanouk is now recalled as a golden age. It came to an end when the United States supported the 1970 coup by Lon Nol. Two years later, Richard Nixon’s secret bombing created chaos and paved the way for the victory of the Khmer Rouge and their queasy alliance with Sihanouk. Since 1979, American rancor toward Vietnam has helped cripple the Hun Sen government, which is the only viable alternative to the Khmer Rouge. U.S. deference to China, Pol Pot’s main sponsor, allowed the Khmer Rouge to thrive. With Hun Sen’s army under siege and Soviet interests in Southeast Asia fading, last week’s policy shift may have come too late to ward off the unthinkable.

U.S. involvement in Peru has so far been more discreet. But military advisers are now to be sent to the Upper Huallaga Valley, where Sendero is growing in strength. Poverty-stricken peasants have moved en masse into coca production in the valley and Sendero presents itself as their protector. Washington dismisses the parallels between the drug war in the Andes and the early U.S. buildup in Southeast Asia. But according to the Peruvian reporter Gustavo Gorriti, writing in the New Republic, Sendero sees the arrival of U.S. troops as the missing piece in its puzzle and now relishes the idea of turning the insurgency into a “war of national resistance,” in which “90% of the population would follow us.”

The Khmer Rouge close in on Phnom Penh; Sendero Luminoso encircles Lima. And Washington remains oddly blind to the connective tissue that joins the United States to their success.