President Trump’s efforts to send National Guard troops to big cities, punish media organizations and pressure universities and private businesses are all unpopular with voters.

But the continued torrent of policies and tactics has not further weakened Mr. Trump’s overall standing, according to a new poll from The New York Times and Siena University. Instead, Mr. Trump continues to retain the support of roughly nine out of 10 Republican voters.

The net result: an unpopular president with an unchanged approval rating of 43 percent.

At the start of his term, Mr. Trump’s approval rating fell from its post-election highs, and it remains weak compared with his predecessors at this point in their presidencies. But over the last several months, his rating has been resilient and stable, reflecting that most voters’ opinions on him have hardened.

The new poll comes as the federal government is racing toward a shutdown on Wednesday, an impasse that has political risks for both Mr. Trump and congressional Democrats.

Voters said they would be likeliest to blame both sides if the government shuts down. But independent voters said they were twice as likely to assign blame to Mr. Trump and Republicans than to Democrats. At the same time, two-thirds of voters warned that Democrats should not shut down the government if their demands are not met.