The assertion that Iran's 'toughest battle has only just begun' suggests a significant escalation in geopolitical and economic pressures facing the Islamic Republic. This statement, often made by analysts observing international relations and regional conflicts, points to a multifaceted challenge that goes beyond immediate military or political confrontations. The mention of a potential US blockade and its impact on the regime's economic base and political control highlights the central role of sanctions and economic warfare in contemporary international diplomacy, particularly concerning Iran.

For years, Iran has been under various forms of international sanctions, primarily from the United States, in response to its nuclear program, support for regional militant groups, and human rights record. These sanctions have had a profound effect on Iran's economy, leading to currency devaluation, inflation, and reduced access to global markets. An intensified blockade, as suggested by the expert, would represent a significant tightening of these measures, aiming to cripple the regime's ability to fund its activities, both domestically and internationally. The economic hardship inflicted by such measures can have a dual effect: it can weaken the ruling elite's resources, but it can also lead to increased suffering for the general population, potentially fueling social unrest.

The phrase "increase the cost of political control" implies that economic pressure can destabilize the regime from within. As the economic situation deteriorates, the government may face greater challenges in maintaining public order, suppressing dissent, and projecting an image of strength and stability. This could manifest in increased protests, strikes, or even more organized opposition movements. The regime's response to such internal pressures, whether through increased repression or attempts at reform, will be crucial in determining its long-term survival.

Furthermore, Iran's 'toughest battle' likely extends to its regional influence and its relationship with global powers. The ongoing tensions with the US and its allies, coupled with regional rivalries, create a complex strategic environment. The effectiveness of any blockade would also depend on the cooperation of other international actors, as well as Iran's ability to circumvent sanctions through illicit trade or by forging new alliances. The coming period is poised to be a critical juncture for Iran, testing its resilience and its capacity to navigate a landscape of intense external pressure and potential internal challenges.