Before she died, Anna Politkovskaya was often besieged in her office by queues of bereaved Russians hoping she might investigate murders that police and the judicial system had ignored. That system is itself in the dock in Politkovskaya's murder trial, which began yesterday in Moscow. There has been no more important test of Russia's commitment to an independent judiciary since the fall of the Soviet Union.

Politkovskaya was a quiet, bespectacled mother of two, and the bravest Russian reporter of her generation. She was shot dead outside her apartment building two years ago, on Vladimir Putin's 54th birthday, while working on a story about the torture of civilians in Chechnya. For seven years she had covered the second Chechen war with unmatched stamina and little thought for her own safety. Her newspaper, Novaya Gazeta, continued to publish her stories on cruelty by and to Russian soldiers in the northern Caucasus long after the rest of the country's mainstream media dropped the subject. Her killing bore the hallmarks of a contract hit.

At the start of that war, which coincided with Mr Putin's rise to power, he vowed to replace the near-anarchy of the Yeltsin years with a “dictatorship of the law”. In March this year his successor, Dmitri Medvedev, promised an end to “legal nihilism”. At least both men recognise the importance of being seen to strive for an effective judicial system. But their words have yielded few significant reforms.

In the Politkovskaya case, four men have been charged but none is accused of actually carrying out her murder, or of ordering it. Police investigators have won praise for their doggedness and have named the alleged gunman as Rustam Makhmudov, a Chechen. But they accuse the security services of systematic obstruction and of helping Mr Makhmudov to evade capture. He remains at large.

The best that can be said of this trial is that it is happening and open to the public. Of the 41 other murders of journalists in post-Soviet Russia, most remain unsolved and many have received only the most desultory investigation: the power of corrupt officials and wealthy business figures to silence press criticism by force is matched by their power to shut down the due process that should follow.

Mr Medvedev, a lawyer by training, now has an opportunity to make good his pledge to boost respect for the law. Like his predecessor, he maintains a pretence that the judiciary is independent of the Kremlin. But this does not mean that he should withhold comment on this case. On the contrary, he should make a public statement supporting the decision to open the Politkovskaya trial to the media. He should advocate long-term protection for its participants at taxpayers' expense if they request it, and he should press for the police investigation to continue until Mr Makhmudov, too, is brought to trial.

Creating genuine independence for the judiciary from the other branches of Russia's Government is the single toughest challenge facing its outnumbered reformers. It is also the most important. Without disinterested enforcement, no law has meaning. And without meaningful laws, Russia will continue on its well-oiled slide towards kleptocracy. Politkovskaya deserves justice, and her country needs it.