Israeli lawmakers will vote Monday on the first major bill in the government's plan to weaken the judiciary, despite six months of protests and American pressure against the most significant shakeup to the court system since the country's founding.

After rumors last week that Israeli Prime Minister Benjamin Netanyahu may back down on the vote or even soften some of its components, the 73-year-old leader is moving forward with it.

Members of the Knesset, Israel's parliament, are voting on the so-called reasonableness bill, which would strip the Supreme Court of the power to declare government decisions unreasonable.

It is the first major piece of the multi-pronged judicial overhaul plan to get this far in the legislative process. Lawmakers on Sunday began a marathon debate on it which lasted until the following morning.

The overhaul has split the country, with hundreds of thousands taking to the streets in protest. Here's what you need to know about it:

What are the changes?

The judicial overhaul is a package of bills that each need to pass three votes in the Knesset.

While Netanyahu and his supporters say it is meant to rebalance powers between the branches of government, critics say it poses a threat to Israeli democracy and to the independence of the judiciary.

The reasonableness doctrine is not unique to Israel's judiciary. The principle is used in a number of countries, including the United Kingdom, Canada and Australia.

The standard is commonly used by courts there to determine the constitutionality or lawfulness of a given legislation, and allows judges to make sure that decisions made by public officials are "reasonable."

The standard was used this year when Netanyahu dismissed key ally Aryeh Deri from all ministerial posts, in compliance with an Israeli High Court ruling that it was unreasonable to appoint him to positions in government due to his criminal convictions and because he had said in court last year that he would retire from public life.

Other elements of the overhaul would give the right-wing government more control over the appointment of judges, as well as remove independent legal advisors from ministries. Those bills have not yet advanced as far in the legislative process as the reasonableness bill.

The prime minister and his supporters argue that the Supreme Court has become an insular, elitist group that does not represent the Israeli people. They say it has overstepped its role, getting into issues it should not rule on.

Defending his plans, the prime minister has pointed to countries like the United States, where politicians control which federal judges are appointed and approved.

Critics also say Netanyahu is pushing the overhaul forward to protect himself from his own corruption trial, where he faces charges of fraud, bribery and breach of trust. He denies any wrongdoing.

Another bill, already voted through in March, makes it more difficult for a sitting prime minister to be declared unfit for office, restricting the reasons to physical or mental incapacity and requiring either the prime minister themselves, or two-thirds of the cabinet, to vote for such a declaration.

Why do these changes matter?

Should the overhaul pass, the changes will be the most extreme shakeup to Israel's judiciary since its founding in 1948.

Proposals to change the judicial process aren't new, as figures from across the political spectrum have in the past called for reform.

Israel, which has no written constitution but only a set of quasi-constitutional basic laws, has had a relatively powerful Supreme Court, which supporters of the changes argue is problematic.

But the Supreme Court is the only check on the power of the Knesset and the government, since the executive and legislative branches are always controlled by the same governing coalition.

Critics say the overhaul will destroy the only avenue available to provide checks and balances in the governing of the country. They also warn it will harm the independence of the Israeli judiciary and will hurt rights not enshrined in Israel's basic laws, like minority rights and freedom of expression.

Netanyahu rules over the most right-wing government in Israel's history, including both ultra-nationalist and ultra-religious parties. Some members of the government have come under fire for expressing extremist views.

According to polling released in February by the Israel Democracy Institute, only a minority of Israelis support the changes. The vast majority -- 72% -- want a compromise to be reached and, even then, 66% think the Supreme Court should have the power to strike down laws and 63% of Israelis think the current method of appointing judges should stay as it is.

Millions of Israelis oppose the bill, including dozens of business leaders. Even Netanyahu's own defense minister, Yoav Gallant, has called several times for delaying the overhaul in order to seek broad consensus. Netanyahu said he was dismissing Gallant earlier this year for criticizing the overhaul, but never went through with the firing.

A group of 150 leading Israeli companies went on strike Monday to protest Monday's bill.

Opposition to the overhaul has also reached Israel's security establishment with members of the military protesting the bill and more than 1,000 Air Force reservists vowing to stop volunteering if Monday's bill passes.

What are Israel's allies saying?

Israel's allies, including the United States, have expressed concern about the overhaul.

US President Joe Biden last week sent a message to Netanyahu via the New York Times' Thomas Friedman, saying that the prime minister is risking the US-Israeli relationship should the overhaul pass without broad consensus.

"This is obviously an area about which Israelis have strong views, including in an enduring protest movement that is demonstrating the vibrancy of Israel's democracy, which must remain the core of our bilateral relationship," Biden told Friedman.

"Finding consensus on controversial areas of policy means taking the time you need. For significant changes, that's essential. So my recommendation to Israeli leaders is not to rush. I believe the best outcome is to continue to seek the broadest possible consensus here."

Netanyahu is yet to receive an invitation to the White House, but Israel's President Isaac Herzog -- who has been trying to forge a compromise between government and opposition on the overhaul -- was invited to meet Biden in Washington last week.

On his trip, Herzog called America "our greatest partner and friend," while also acknowledging criticism from some House progressives.

What happens if the bill is passed?

The Israel Bar Association is already preparing a legal challenge to Monday's bill, the lawyers' group said Sunday. Its executive, the Bar Council, approved the decision to petition the Supreme Court to cancel the reasonableness law if it passes on Monday, the Bar said.

The Bar also warned that it will shut down "as an act of protest against the anti-democratic legislative process," the statement said. That means the Bar Association would not provide professional services to its members, and not that lawyers would go on strike.

Petitions for the Supreme Court to throw out the law, and to block its implementation until there is a court ruling, are expected to be filed when the court opens for business on Tuesday.

If the Supreme Court rules the unreasonableness law itself as unreasonable, invalidating the law that strips the court itself of its powers, this could trigger a constitutional crisis that sets the government and the court against each other.