What evidence can I use to link the ideology between the leaders before the cold war began, even before 1918? was there any between US and the Soviets?
I want to know why some historians thought that there was always ideology conflicts between the two nation before in the very, very early day such as in the 1917 etc.. or was it even before than?
The Russians and the United States had often worked together as "allies" but these alliances were almost always alliances of circumstance rather than choice. There was a deep distrust of any foreign government that had been a part of the Russian psyche for centuries. This distrust led them to make bargains with other governments but again, when circumstances changed, they would quickly break them.
If you examine the alliances during the two World Wars, it is clear that the leaders of both nations never trusted each other. This is particularly evident in World War II when neither Churchill nor Roosevelt trusted Stalin and Truman didn't trust him either when Roosevelt passed away. There was even a race to Berlin to see who could capture more of Germany and the rest of Europe as there was already some understanding that the Soviets would keep what they got.
The xenophobia that served to deter the Soviets from making strong allies was certainly a barrier to a real alliance but the real differences were ideological in that the West and the United States were afraid of and vehemently opposed to communism and unwilling to see it as viable or normal. So despite being "allied" with Russia in both World Wars, ideologically the US often had more in common with their enemy in Germany than they did with their Russian or Soviet allies.