Beirut, Lebanon (CNN) For weeks, loud and angry demands reverberated across Iraq and Lebanon , rattling their political leadership. Elites publicly acknowledged the popular indictment against them, and serious political concessions appeared inevitable. It signaled a shaking up of the powers that be that would've been unimaginable even a month ago.

Then, in the span of just three days this week, governments in Iraq and Lebanon have agreed to resign . Protesters have rejoiced, but many also recognize that a long and complicated road lies ahead.

Unlike much of the Arab world, Iraq and Lebanon are not ruled by autocrats, and a change in government rarely spurs a shift in domestic policies. Instead, demonstrators say these countries are governed by democratically-elected kleptocracies, with the political elite deeply entrenched thanks to convoluted sectarian power-sharing systems.

In both cases, protesters face the formidable task of changing entire political systems, and not just their cabinets, to tackle their grievances.

This became clear in Lebanon when, no more than 24 hours after resigning as prime minister, Saad Hariri was already emerging as a favorite for the same post. In Iraq, Prime Minister Adil Abdul Mahdi's resignation will be effective only when a successor is found.

"To the Iraqi protesters, the resignation (of Abdul Mahdi) in some parts is a welcome move in terms of the protests yielding some sort of result," said Amnesty International's Iraq researcher Razaw Salihy. "But it's nowhere near enough in terms of the demands that protesters have."

"(These are) not only the resignation, but also that everybody in government be held accountable for long-standing human rights violations as well as ... very deep corruption in government," said Salihy.

In an interview with CNN's Becky Anderson, Interior Minister for Lebanon's caretaker government and Hariri ally, Raya al-Hassan, also acknowledged the Lebanese government's resignation as only "a partial victory."

"I think this is a portion of what they were demanding," Hassan said. "Definitely we need a clean government. The protesters have set the bar very high for us, so we cannot anymore try to weasel our way out of that commitment."

Lebanese PM Hariri hands resignation to Lebanon President

But even if politicians have sincerely committed themselves to eradicating corruption -- and there is a deep distrust among protesters about this -- the circumstances may prove intractable. Among the main hurdles is the political system that both countries have in common.

After the 2003 American invasion deposed Iraq's long-time dictator Saddam Hussein, the US introduced confessionalism -- the same colonial-era system imposed in Lebanon -- which divides power based on sectarian affiliation. Protesters in both countries point to it as the root cause of endemic corruption and cronyism.

Another complicating factor is Iran's growing influence. In Iraq, the Tehran-backed Popular Mobilization Units (PMUs) played a major role in expelling ISIS from the country, but came to wield great power in government. In Lebanon, Hezbollah -- the Iranian-backed political and militant group — mounted a guerrilla campaign which eventually saw Israel make a messy withdrawal from south Lebanon after 18 years of occupation. It later built a political coalition, comprised of Christian and Shia allies, into the country's strongest political force.

Iran didn't create the status quo that people rose up against in either country, but it has a great stake in maintaining it. And protesters galvanized by deep economic grievances that accumulated over many years of government mismanagement soon found themselves facing off with Iranian-backed forces, or their supporters.

In Lebanon, Hezbollah initially acknowledged the protests, which began in mid-October , as legitimate, but later tried to discredit the movement, saying parts of it were driven by a conspiracy against the group.

Supporters of Hezbollah and its political allies in the Amal movement have twice attacked protest sites. The group has also opposed the resignation of Hariri's national unity government, which included Hezbollah and its allies.

Hezbollah's stance has drawn the ire of protesters, even among those most sympathetic to the group. While not itself notorious for economic corruption, Hezbollah has positioned itself, at this critical moment, as the guardian of Lebanon's self-serving establishment.

When the demonstrations began in Iraq in early October, there was "very little talk of the downfall of the regime," said Amnesty's Salihy, but the security forces' violent response to the protests fomented political discontent.

"The presence of certain factions of the Popular Mobilization Units in southern governorates, where they rule with an iron fist, has added to the grievances," Salihy said, adding that resentment toward the government grew when it became clear that the PMUs were beyond its control. More than 200 people have been killed by security forces since the protests erupted, according to Amnesty.

US Secretary of State Mike Pompeo said Friday that the Iraqi government's investigation into the violence in early October "lacked sufficient credibility" and that "the Iraqi people deserve genuine accountability and justice."

Anti-government protesters in Lebanon celebrate after Saad Hariri announced his resignation.

Now, less than a month later, the resignations prompted by protesters in Lebanon and Iraq could mark a turning point, potentially leading to the political concessions needed to rescue both countries from increasing decay.

Lebanon's president (and Hezbollah ally) Michel Aoun on Thursday called the sectarian system a "sickness" and vowed drastic political reform. In Iraq, Abdul Mahdi's resignation displeased Iran, but could be a first step in remedying corruption.

Whether or not the protesters can cause systemic change -- beyond a reshuffling of power -- is less clear. In Iraq, the PMUs could find themselves on the back foot and be forced into concessions. In Lebanon, Hezbollah could retreat from the political landscape in attempt to preserve their arms. For many years the group has opposed Lebanon's neoliberal economics, even as it found itself active participants of this system. On Friday, Hezbollah chief Hassan Nasrallah toned down his opposition to the protests in a speech that called on the next government to be transparent and to address the demands of the protesters.

But corruption in Iraq and Lebanon extends well beyond Iran's role in these countries, and the US and Saudi Arabia have also backed prominent political players in the system.

The question now is whether the protesters have the wherewithal to tackle the plethora of players, external influences and business interests that have for years sustained these establishments.

CORRECTION: This story has been amended to correct the date on which Hezbollah chief Hassan Nasrallah made a speech about the protests in Lebanon.