The Russians are hitting out with a vengeance in all quarters. Whether internal or external, great or small, no challenge to Soviet authority now goes unrebuked.

Perhaps the toughness is a mere bargaining maneuver. But there is a true danger - a danger that Washington must now count as its first business to avert - that Moscow is being pushed by the ineptitude of the Carter administration along the classic curve that leads from mere defensive tactics to a hardline strategy.

The most prominent target of the harsher Soviet mood has been Washington itself. Official Soviet publications have criticized President Carter by name for his stand on human rights and for his original disarmament proposals.

The Russians canceled the July 4 speech that Ambassador Malcolm Toon was due to read on Soviet television. Toon was then called in and dressed down severely by Leonid Brezhnev himself. In addition the Russians have denounced, with a fine even-handedness, both the decision of the administration to build the neutron bomb and to not build the B-1 bomber.

Before that Moscow had picked on a bunch of smaller troublemakers. The dissidents inside the Soviet Union are now being hammered in arrests, indictments, trials and long prison sentences. The West European Communists who would like to take their distances from Moscow got the wet mitten in the form of a harsh attack on Spanish Communist leader Santiago Carrillo.

The Chinese got theirs, in April, when Moscow sent Peking an extremely harsh note and followed with a Pravda editorial that raised the specter of war.

West European sentiment for a strong stand on human rights was smacked hard during recent talks with German officials visiting Moscow, and French officials when Brezhnev went to Paris last month.

Moscow's tough line almost certainly started off as a tactical response to the emphasis put by the new Carter administration on human rights and a new approach to arms control. As I reported from Moscow in May, the Russians felt that Carter could not keep up the early pace he had set on human rights or arms control. By standing tough on all issues, they felt they could force an American retreat that would be visible to the world.

Though not very visible, a retreat has in fact taken place. The tough armscontrol proposals put forward by Secretary of State Cyrus Vance in Moscow were watered down considerably when the secretary met with Foreign Minister Andrei Gromyko in Geneva two months later. Human-rights statements made by the President and others have been moderate.

When that softening produced no results in Russia the administration began casting about almost desperately for some means of dialogue. It raised the possibility of a non-business summit between the two leaders. But the Russians reacted negatively to that not bad idea when Carter began speaking of it publicly before they had agreed.

In the face of that semi-rebuff, the White House evidently felt the need to prove that it was approaching Soviet-American relations in a serious and thoughtful way. An apparently second rate study by the National Security Council - Presidential Review Memorandum 10, which modified extreme estimates made of the Soviet threat in the Ford administration - was puffed up as an example of deep think. But the publicity only invited questions about whether the Pentagon truly supported the revised estimates, and why the Carter administration bowled along in a multitude of moves toward Moscow before the review was done.

Now Washington is in a quandry. There are some areas - notably the Middle East and China - where the Carter administration could usefully make life less easy for the Russians. But an across-the-board hardening would destroy the arms-control negotiations, which the administration rightly wants to keep in motion.

My own sense is that the Carter administration now has to make a fresh start with the Russians. It not only needs to undo the false moves made on human rights and arms control. It - even more importantly - needs to disabuse Moscow of any impression that a tough line will bring American concesions. Probably the best way to do that, if an informal summit cannot be arranged, is to send to Moscow a special envoy trusted by the Russians in the past and without any part in the grave misunderstanding that has come to dominate Soviet-American relations in the last six months.