Their massed ranks are fueled by a deep antagonism towards the theocratic regime, but Iranians are not going to succeed in overthrowing Ayatollah Ali Khamenei.

That day will almost certainly come at a future point, but not because of the ongoing protests against the government's deception over its downing of a civilian airliner. Two factors explain why.

First and most important, 2020 Iran is not yet 1979 Iran. The government's security apparatus remains loyal and retains an effective monopoly on coercive instruments of power. Until that changes, the protesters won't be able to overthrow the regime. Iran's leaders have killed hundreds of thousands of innocent Muslims in Syria, and have a similar lack of compunction about massacring their own people. In turn, as long as their security forces continue following orders, the regime can simply kill enough people to force the remainder back into their homes.

This is a critical point.

The historic lesson of successful revolutions is that the coercive state must abandon the center in order for the revolutionaries to succeed. Consider, for example, the distinction between the 1905 Russian revolution and Russia's 1917 revolution. The first revolution failed because the Tsar's forces crushed the protesters. Although World War I's impact was significant in motivating protest anger in 1917, common public anger over economic suffering and political oppression was sustained between 1905 and 1917. What changed was that those same forces who had gunned down protesters in 1905 refused to follow the Tsar's orders 12 years later.

Iran right now is 1905 Russia, not 1917.

As with the November 2019 energy protests, Iran's leaders are deploying their security forces to corral, tear gas, and as leaked video suggests, gun down those now on the streets. They will keep doing so.

The second challenge here is that even if Iranian police forces and conventional army units become reluctant to kill their fellow citizens, the regime will deploy others to replace them. Take the Islamic Revolutionary Guard Corps' Basij militia. A proudly thuggish force that is hundreds of thousands strong, the Basij has both military power and ideological fervor. Many of its followers will die before surrendering the Islamic revolution.

At the same time, Iran's MOIS intelligence service and the Islamic Revolutionary Guard Corps' internal security forces will use intimidation and targeted violence to ensure that otherwise skeptical security forces do not throw their support behind the protesters. As we've seen in Venezuela, even where a majority of security forces oppose the regime, a well-funded and organized campaign of intimidation has ensured those forces remain loyal to Nicolas Maduro. In such situations, only an external influence or inspirational leader can tip the balance.

And yet, there is hope.

Iran's population remains educated, very young, and angry. Just as the energy price crisis was the spark that lit the November 2019 protests, and the airline disaster the spark here, Iranians' true motive is to end a regime that cares only for its domestic cronyism and its imperialist foreign policy agenda.

Each year, that motive only reaches more Iranians. The advent of social media has also provided a vast new architecture for organizing protests and disrupting the regime's grip on power. As I'll explain in my next piece, the United States is actively supporting these efforts. And as the regime continues its economic isolation, its ability to lubricate security force loyalty will grow. Eventually, those forces will find a leadership and critical mass of power to crush the Basij and win Iran's freedom.

But Iran isn't there just yet.