WASHINGTON — Donald J. Trump’s campaign on Thursday reaffirmed its extraordinary embrace of Russia’s president, Vladimir V. Putin, signaling a preference for the leadership of an authoritarian adversary over that of America’s own president, despite a cascade of criticism from Democrats and expressions of discomfort among Republicans.

“I think it’s inarguable that Vladimir Putin has been a stronger leader in his country than Barack Obama has been in this country,” Gov. Mike Pence of Indiana, Mr. Trump’s running mate, said on CNN, defending Mr. Trump by echoing his latest praise for the Russian leader, offered Wednesday night in a televised candidate forum.

Hillary Clinton excoriated Mr. Trump for asserting that Mr. Putin is a better leader than President Obama, saying it was “not just unpatriotic and insulting to the people of our country, as well as to our commander in chief — it is scary.”

She seized on Mr. Trump’s assertion in the televised forum that Mr. Putin’s incursions into neighboring countries, crackdown on Russia’s independent news media and support for America’s enemies were no more troublesome than Mr. Obama’s transgressions. She said it showed that, if elected, Mr. Trump would be little more than a tool of Mr. Putin.