THE rhetoric is harder and more hostile than it was during the original ''cold war,'' but it isn't the same thing. On the surface we have the President of the United States calling the Soviet Union an ''evil empire.'' Moscow hits back, calling the President a ''shameless liar.'' Joseph Stalin and Harry Truman were blunt and forthright men who didn't mince words, but neither of them went in for public invective like that.
Behind the relative surface restraint of the first ''cold war'' was a series of true crises. Today there is no true crisis behind the invective. It can be a useful exercise in perspective to refresh our memory of the real ''cold war.''
On April 1, 1948, the Soviets closed all surface access routes to West Berlin. Washington considered sending an armored train through the blockade. On second thought Washington decided on an airlift. For the next 18 months, until Sept. 30, 1949, British and US transport planes kept the city of West Berlin alive and working with an endless supply of food, industrial supplies, and even coal.
A total of 2,343,315 tons of supplies of all kinds was airlifted to West Berlin, often with Soviet military aircraft buzzing menacingly close to the planes of the air shuttle. It took cool nerves to run that shuttle, and keep it running.
The second was the Cuban missile crisis. That was more dangerous. For six days in 1962, from Oct. 22 to 28, the world held its breath while Soviet ships with strategic missiles on their decks steamed steadily toward Cuba and scores of ships of the US Navy took up intercepting positions.
There was no question about what might happen. President Kennedy could not allow missiles to be landed in Cuba. He could not allow those already there to remain. The ships had to be turned back and the missiles already in Cuba had to be reloaded and also sent back.
The armed might of the US prepared for whatever action might be necessary. The airborne divisions moved to their takeoff fields. The landing craft began loading assault infantry at the seaports. The fighter squadrons moved to Florida , lined up, and were ready.
There is nothing like that going on today. Nor is there the serious prospect of any such military confrontation between US and Soviet armed forces.
True, things are getting a little tight in the Middle East, with Iran and Iraq shooting at oil tankers in the Gulf. But there are no Soviet troops in either Iran or Iraq and no Soviet naval units playing games inside the Gulf.
There is talk in Washington of being ready to help the Arab countries defend themselves against Iran if matters get worse. But Washington is stressing its readiness to help only if requested. It is not moving in US troops on its own initiative.
Only once since the Cuban missile crisis in 1962 have US and Soviet forces been in sight of a possible military confrontation. That was during the 1973 war when the Israelis surrounded an Egyptian Army and the Soviets alerted an airborne division as if to go to the aid of the beleaguered Egyptians. The US put its armed forces on a Class B alert. But it also ordered the Israelis to cease and desist. The crisis passed.
The words today are startlingly hostile, yes. But ships daily load grain in American ports for the Soviet people. When the Korean airliner was shot down, the first actual reaction in Washington was assurance to American farmers that Mr. Reagan would not again embargo grain to the Soviets.
Those of us who remember the Cuban missile crisis know what a sense of real danger and tension in US-Soviet relations feels like. You can never forget. It is a moment when you know that a single misstep in either Moscow or Washington could set nuclear missiles flying. And then there was that marvelous moment of relief when the word was flashed that the Soviet ships had turned around and were headed back toward their home ports.
This new ''cold war'' is full of words and postures. The words are insulting, but behind the curtain of insulting words, Soviet Ambassador Anatoly Dobrynin drops in for a quiet chat with President Reagan or Secretary of State George Shultz. This is different.