Prime Minister Vladimir Putin warned Russians on Monday that without him, ethnic tensions could tear the country of 140 million apart.

Putin, who is likely to be reelected as president in March, is the most popular politician in Russia by far with an approval rating over 60 percent.

Opposition to the two time president and his ruling United Russia party is mounting however. Especially older people for whom the collapse of the Soviet Union — and event that Putin has called a “disaster” — hasn’t produced a significant improvement in living standards increasingly sympathize with the communists who doubled their share of the vote in last year’s parliamentary elections.

A minority of younger, liberal Russians is very vocal in their opposition to what they perceive as the corrupt ruling class in the Kremlin. Putin has dismissed their protests and seems more concerned about the rise of nationalists who have joined left-wing demonstrators in rallies against what they describe as the “party of swindlers and thieves.”

In a newspaper article on Monday, the prime minister wrote that after the disintegration of the Soviet Union, “we were on the edge — and in some regions over the edge — of civil war.” In Central Asia and the Caucasus, socialist republics seceded from the union in the early 1990s sometimes after years of violence.

“With great effort, with great sacrifice we were able to douse these fires,” Putin wrote in the Nezavisimaya Gazeta. “But that doesn’t mean that the problem is gone.” In the Caucasus in particular, nonethnic Russians continue to fight for autonomy.

During Putin’s first presidency, Russia waged a bloody war in Chechnya to prevent the region, which is 94 percent Muslim, from declaring independence.

In 2008, the Russian army invaded Georgia to stop it from annexing South Ossetia which had largely been under de facto Russian control since 1992.

The unrest isn’t confined to the mountainous southwest of Russia anymore. In March 2010, at least forty people were killed by suicide bombings in two of Moscow’s metro stations. In January of last year, 37 people died in a terrorist attack on the city’s airport. Both attacks were attributed to radical Islamists from the Caucasus region.

Apprehension of the separatist threat has mounted as a result of the attacks. Labor migration and higher birth rates among Russia’s Muslim population are cause for alarm among ethnic Russians who are mostly Orthodox Christians.

Putin likes to portray himself as the strongman who will crush the sectarian menace but the nationalist sentiment within Russia is also a challenge to his vision of a united Eurasia that he hopes will revive his country’s status as a continental superpower. He has already drawn Belarus and Kazakhstan into a customs union and free-trade zone and hopes that other former Soviet satellite states will join once he is president again.

Steering a fine line between national pride and geopolitics, Putin praised Russian culture which he wrote “is the glue holding together the unique fabric of this civilization” but warned that, “If a multiethnic society is infected by nationalism, it loses its strength and durability.”

The best way to stem immigration, he added, was to improve economic conditions in Russia’s outer regions and neighboring states. To that end, Putin touted his Eurasian trade union. He may struggle to convince seniors and working-class voters that open borders are what will improve their economic prospects though.

Putin will likely be reelected by a wide margin if only because there isn’t a viable alternative but his third term could be his toughest one yet. Russia’s growth forecasts are more optimistic than most other developed nations’ but as is the case in Europe, mounting economic disparity could give rise to a populist candidate or faction to challenge the status quo.