During his time in the Kremlin, Vladimir Putin has drawn on two potent sources of political strength: high oil prices, which fell into his lap during the boom; and patriotic fervour, which he stoked by engineering regional conflicts. Now the oil price is falling like a stone. Will the Russian president be able to rely on patriotic mobilisation alone?

The past decade brought two periods of surging oil prices: one that ended in 2008 amid the flames of the financial crisis; and another that began barely three years later. But last week a barrel of oil fetched as little as $70, from $105 in June, and Russian producers must be feeling the squeeze.

The latest slowdown marks a moment of danger for Mr Putin. In the decade and a half since he first became president, the government has strengthened its control over oil and gas and increased its role in the financial sector. The creeping tide of nationalisation eroded incentives for investment, and swept away the resources needed for private investment. This is hardly without precedent; in resource-rich countries people are usually enthusiastic about nationalisation. But they expect benefits.