Tens of thousands of Israelis opposed to a judicial overhaul sought by the prime minister, Benjamin Netanyahu, marched to Jerusalem on Saturday as pressure mounts on his rightwing government to scrap a bill that would curtail the supreme court’s powers. Carrying Israeli flags, a long column of protesters hiked up the winding highway to Jerusalem under a scorching summer sun, to the sounds of beating drums and anti-government chants and cheers. The government’s attempt to change Israel’s judiciary has plunged the country into one of its worst political crises, sparking nationwide protests, denting the economy and stirring concern among western allies. Protesters have been walking for days through a heatwave, camping out overnight and met by local people offering food and drink, with their numbers swelling as they reached the city gates in an unprecedented sight. They plan to rally outside parliament before a Sunday debate and subsequent vote on the bill, which would limit the supreme court’s powers to void what it considers “unreasonable” government or ministerial decisions. Netanyahu’s religious-nationalist coalition says the bill is needed to balance out the branches of power because the court has become too interventionist. Critics say the amendment is being rushed through parliament and will open the door to corruption and abuses of power. Polls suggest widespread misgivings among Israelis. Washington has urged Netanyahu to seek consensus on any judicial changes, which it said should keep Israel’s judiciary independent. The crisis has even sown divisions within the military, long viewed as an apolitical melting pot for a fractious society, with concerns about war-readiness voiced on both sides of the debate. Dozens of former security officials, including the heads of the military, police and the Mossad, some of whom served under Netanyahu, published an open letter to the premier on Saturday urging him to call off the vote and negotiate widely agreed reforms instead. “The legislation is crushing those things shared by Israeli society, is tearing the people apart, disintegrating the IDF [Israel Defense Forces] and inflicting fatal blows on Israel’s security,” the letter said. Netanyahu, who is on trial for corruption, which he denies, has said he has been striving for broad agreements and has placed the onus on opposition parties to make compromises.