The US is no longer is capable of toppling the head of state of Syria, and Turkey and Saudi Arabia played crucial role to topple Mr. Bashar Al – Assad as head of state of Syria. It is very obvious that he was able to maintain power because Russia provided military aid to Mr. Al – Assad to confront the insurgent groups. In addition, the Islamic Republic of Iran provided military aid to the regime in order to keep the regime intact in place. If the regime in Iran would not provide military aid to Mr. Al – Assad, it was a good possibility for the US to do regime change in Iran too. Now, the US no longer can ensue the policy of the regime change in the Middle East.
The trouble comes here that Turkey as member of NATO aided insurgent groups in Syria and Iraq. Moreover, Saudi Arabia too aided the insurgent groups to topple the head of state in Syria and Iraq. The above nations were instrumental for regime change policy in the Middle East. However, they failed to topple the Islamic Republic of Iran. In fact, the regime in Iran has gained more power in the region, and galvanized solidarity among Shia Muslims in the region. Now, the US really has no power in the region. The Saudi Arabia remains vulnerable in the region since Iran excommunicated with Saudi over pilgrim issue. The regime in Saudi would face serious economic consequences for its role in the region for aiding the US for doing regime change in the Middle East. Furthermore, Turkey too would face serious economic consequences from the Middle East nations.
There is also matter of Israel that what it will happen to it. Israel would face serious military consequences by its adversaries, and the US will play major role in the region, but not in a sense of regime change.
All in all, the situation in the Middle East has become complicated, and no longer realpolitik is the common currency, but really diplomacy will become a common currency in the Middle East.