History is life's teacher, says an old Latin wisdom, but it's much much easier to say than to implement it, especially in politics. The experiences of cheated and destroyed countries, as well as their leadership, have been so vast in the 20th and 21st centuries that list is too long to be written. Still, we can for sure make some comparisons, based on correlation between the army strength and the political moves.
In the recent period, we saw a lot of "regime change" scenarios in different forms all over the world, and all of them ended with victory of the USA and its allies. Milosevic, Saddam Hussein, Gaddafi, and so on. The two key pillars of defense are military strength and economic power.
By undermining this two factors, the United States has been able to achieve its goals, except in the case of the Axis of Resistance in the Middle East. It's a wider project and far more immune to US pressures. If we compare the Iranian experiences with the mentioned examples, we can see that Iranian policy is more complex and much better planned. Every political move inside Iran and on a regional level was followed by military strength, balanced in the way to protect political or economic moves. Here's why it's important.
Saddam Hussein was an example of a rabbit mover who thought that he can achieve anything he wants in the short period: waging war against Iran, building a nuclear program without proper air defense, etc. He's the best example what happens when political moves are not followed by a proper military balance of power. After weakening his country in an aggression against Iran, Iraq itself become an easy prey to the Western imperialists. Also, the Iraqi nuclear program was razed to the ground. Ba'athist Iraq began to correct mistakes shortly afterward, but it was too late and it was again overwhelmed by Western powers.
Libya under Muammar Gaddafi is also a good example of where a political-economic policy was also unbalanced. After the fall of the Soviet Union, Libya lost its major arms supplier and their army started to shrink. Despite Gaddafi's high ambitions and participation in various pan-movements, his military did not follow such political moves. Even after 2003, irrespective of the large profit from the oil production, Libya's military capabilities did not improve except in personal security units. When the war broke out in 2011, Libya did not have a proper air defense and ground forces were hopeless during the attack. Such scenario repeated itself all around the world in different forms, but the result was the same: armies and leadership failed, economies collapsed, and regional balance changed.
Iranians were well aware that they can not trust the West, and that every political and economic move must be followed by well balanced military capabilities. Before expansion of their nuclear program, Iranian government expanded its regional security by strengthening ties with their closest allies Syria and Hezbollah, making their own regional safety more realistic. After that, they start to improve their nuclear program as well as air defense. That made them very secured because any attack could create a regional war which can not be a controlled process, and that's the reason why the United States did not engage in conventional military confrontation against Iran.
Slowly developing a well-balanced policy for many years, Iran has learned lesson from previous cases in Yugoslavia, Iraq, and Libya, so they built formidable air defense through reverse engineering and domestic technology. They are perfectly aware that without a reliable air defense they would lose the war before its very beginning. Another important factor is the strategic retaliation capability, namely ballistic missile arsenal, dispersed all around the country and directed against American bases in the region, as well as Israel and Saudi Arabia. Their net of air defense is also widespread and could not be taken so easy.
Air Force is not a branch in which Iran can challenge the United States, therefore it has a limited financial investment, and most money goes to defensive politics and strengthening above mentioned two pillars of defense. Recent construction of a large air defense base near the city of Abadeh shows an important expansion of the Iranian military capabilities.
Finally, we can conclude that Iran has proven to be very successful in its long-term policies regarding the principled regional alliance, strong air defense, retaliation capabilities, and full control of the Hormuz Strait. There was no meaningless spending on expensive but practically useless military equipment, nor engagement in overambitious international policies. Ironically, in numerous Western analyzes, Iranian military approach has been long criticized as slow and ineffective, and in the same time, they praised the rapid arming in the Arab countries. Having a several thousand modern tanks sounds promising in theory, however, the cases from Yugoslavia, Iraq, and Libya have proved that this is insignificant in practice.
Slow but well-planned military development is far more important and its evident from today's balance of power in the Middle East. As the ancient fable teaches us for many centuries, the turtle has again proved to be more successful than the rabbit.