I tried to do so several times, but the fact is/was that I failed.

[nelson13]

Thank you all. I know that when I am talking to foreigners, I can dodge some usages unfamiliar, but it will be slipshod, and I am interested in knowing how to explain the grammar behind.

[nelson13]

How about the following sentence:

America is/was the first and only country to establish a republican without failure.

If I use was, won't there be implications that America is now not?

[bhaisahab]

How about the following sentence:

America is/was the first and only country to establish a republic without failure.

If I use was, won't there be implications that America is now not?

No, it's OK with either "is" or "was". It's factually incorrect though.

[nelson13]

Thank you.

I know I can simplify the things, but I hope to know which form of verb I should use.