Why does Indiana Jones say 'I like Ike'?

Question

In Indiana Jones and the Kingdom of the Crystal Skull, short while after the beginning of the movie, Irina Spalko captured Indy and force him to lead the U.S soldiers military base which contains bunch of crates. Then, they've opened a highly magnetic crate which contains a weird creature. Meanwhile, Indy attempts to escape, however the attempts failed because Mac was pointing the gun at Indy's head and then reveals he's a spy working for Soviets. In that time, Indy and Mac had a conversation and then finally Spalko asked, 'No defiant last words, Dr. Jones?' to Indy. He replied as, 'I like Ike'.

Here is the script of the movie,

Drop the guns, or Colonel Dr. Spalko is dead.

Why, Mac?

Well, what can I say, Jonesey?

I'm a capitalist, and they pay.

After all those years we spent spying on the Reds?

I thought we were friends, Mac.

I've had a run of bad luck with the cards lately, mate.

Awful. Bloody awful.

I can't go home empty-handed again.

No defiant last words, Dr. Jones?

I like lke.

What does 'I like Ike' mean in this particular context?

Why does Indy say like that?

Answer 1

Irina Spalko was a KGB operative communist working for the Soviet Union. She was attempting to obtain the Crystal Skull in order to give the USSR an advantage over the Americans.

From the screen play:

The barrel of Mac’s gun, pointing directly at Indy’s head.
INDY (cont’d) Why Mac? Why? *
MAC What can I say, Jonsy, I’m a capitalist. And they paid. *
INDY After all those years we spent spying on the Reds?! I thought we were friends Mac.
...
SPALKO No defiant last words, Dr. Jones?
INDY I like Ike.

Indiana Jones was clearly opposed to communism, at the time President Eisenhower was the strongest force against communism. And given that Jones had just learned his friend betrayed him, he wanted to show that he was still loyal American.