Why sanctions won't work

In response to Putin's invasion of Ukraine, the West is proposing "stiff sanctions". Simply put they will not work. First, to prevent Putin from effecting regime change in Ukraine, they would have to bite within a week; that as long as one might reasonably expect the Ukrainians to hold out against the Russian onslaught. Within a week, Putin will likely have deposed Ukraine's President Volodymyr Zelensky and installed his own interim administration. But sanctions won't have desired effect in that short a time; they cause problems over weeks not days and Putin has already buffered himself and Russia from their impact, further lessening their efficacy. 

Sanctions will also have two unwelcome consequences for the West. First, they will cause problems for ordinary Russians which will only serve to bolster Putin's hold on power. Just as the Iran theocracy blames the country's woes on Western sanctions, so will Putin. Secondly, sanctions will also impact businesses in in the West that currently trade with, or do business in, Russia. Over time as the America public comes to accept the Russian installed regime as a "new normal", opposition to lifting sanctions will subside and business interests will prevail. 

One can see how ineffective they are in the US' policy toward China and Afghanistan. China's stance towards the US has hardened in the last five year despite tariffs and sanctions against Hwawei. North Korea continues to develop nuclear weapons. Iran is continuing to enrich uranium. And the Taliban is not becoming more liberal in its attitudes towards women while the Afghan people starve; because of that the West will change course before China, North Korean, or the Taliban. And while sanctions remain in place, Russia will seek to develop trading relations with other countries, further reducing both their medium term impact and making them still less effective as a future deterrent.  

That makes President Biden's reported statement that were Russia to attack a member of the NATO alliance, "the use of military force is not off the table" significant.  It means that the use of military force is not an inevitable consequence were Putin to move against a NATO country in Europe. Given the futility of sanctions and the possibility that Putin could threaten and invade NATO member countries without a military response from the West, he must now feel he has considerably more freedom to act as he pleases.