WASHINGTON — In the days after the 2016 presidential election, Donald J. Trump’s advisers had an unequivocal message about contacts between Russians and members of the campaign team: There were none.

In the ensuing months, as numerous such communications were revealed, the message changed: There was no collusion with Russia’s effort to disrupt the election.

On Monday, President Trump’s lawyer Rudolph W. Giuliani consistently presented a third line of defense: Even if Mr. Trump did collude with the Russians, he committed no crime.

Mr. Giuliani insisted during numerous television interviews that no evidence of collusion existed, but the evolving narrative is a sign of how much Mr. Trump and his aides have had to recalibrate their public message in the face of considerable evidence of contacts between Russia and the Trump campaign, and with the special counsel investigating what — if anything — Mr. Trump knew about them.