President Trump is nearing 100 days without a victory. By way of explanation, he has pointed his Twitter trigger finger at the media, at Democrats in Congress, at conservative House Republicans — at pretty much everyone but himself.

But maybe Trump should hold up a mirror. More than half of Americans think Trump hasn't accomplished much in his first 100 days (56 percent). Of those less-than-impressed Americans, almost half blame the president for getting so little done, according to a new Washington Post-ABC News poll.

Given how rarely Trump expresses humility or regret, acknowledging that he's got a learning curve could help buy him a grace period. Assigning blame elsewhere just doesn't seem to be working for him.

A caveat to this data: It's nearly impossible to separate the blame game from partisanship. Democrats are more likely than others to say Trump has not accomplished much. And only those who doubted Trump's accomplishments were asked who is most responsible. Most Republicans and Trump voters think he has accomplished a good amount.

Also, blaming the president for inaction 100 days in is not unusual. In the first three months of President Barack Obama's term, 49 percent of Americans who thought he struggled to get anything done shouldered him with the blame. (Though they split it 40-40 between President Bill Clinton and Republicans in Congress during Clinton's first 100 days.)

But Trump perhaps has more to prove than his predecessors. To have a successful presidency, he must make good on his central campaign pitch that someone with no previous political experience can govern the nation better than the politicians.

So far, he hasn't been very convincing. His approval ratings are the lowest of any modern president's three months in. His leverage with Congress appears to be little to none. The Post-ABC poll found that a majority of Americans also criticize Trump's temperament, judgment, empathy and honesty — and they don't trust him in a crisis.

Trump, in short, is having a crisis of confidence. And that's why turning to himself when assigning blame for these first 100 days may be so crucial for him to regain his footing. A dose of humility could go a long way, perhaps, if he addressed Americans like this: "Hey guys, I know we've failed to get Obamacare repealed and that my travel ban is stuck in the courts again. But I'm new to this. Give me another 100 days."

This Post-ABC poll has data points that suggest Americans might be ready to hear him out. A majority think Trump is a strong leader. (The percentage is far lower than Obama's, but it's something.)

In addition, hardly any of Trump's supporters have buyer's remorse. Republicans polled think Trump is more in touch with them than the rest of the Republican Party is. In other words: Trump's job approval may be taking a hit, but not among his supporters. They still have faith that his business skills will translate to politics.

The rest of America isn't so sure, and Trump's habit of assigning blame elsewhere doesn't seem to be assuaging their concerns.

Scott Clement contributed to this report.