The giant truck strike in
Several times during the so-far nine-day strike, Temer's center-right government has declared it's all over, only to find itself negotiating with protesters again.
When Temer agreed to the strikers' main demand of lower diesel prices on Sunday, road blockades persisted across the country Monday and at least partly into Tuesday.
When he did attempt to stand firm, calling out the army to escort food and fuel past picket lines under armed guard, that only restored supplies to a trickle.
Even before the crisis, Temer was the most unpopular Brazilian president on record. And with elections coming up in October, which he will not contest, he was already a lame duck.
But the strike debacle raises the question for some of whether he can govern at all in the remaining seven months of his administration.
"We've reached the point where the Temer government has nothing more to offer. He will end his mandate in extreme weakness, a zombie administration," said Andre Cesar, at Hold consultancy in Sao Paulo.
Cesar said he wasn't even sure Temer could last that long.
The scenario of an early Temer exit is increasingly being whispered in political circles too, Folha newspaper reported Tuesday, with the headline: "Chances are growing for Temer not to complete his mandate, members of Congress and the Supreme Court say."
Dropping the economic ball
Temer came to power in 2016 with the self-declared mission to put order back in Brazil after more than a decade of what he said was ruinous leftist rule.
He wasn't elected into the office, taking over automatically after helping to engineer the impeachment of leftist president Dilma Rousseff.
That earned him hatred on the left in Brazil. On the right, Temer was initially welcomed, seen as bringing in a team of serious economists who could steer the country out of its deepest recession in history and lure back fleeing investors.
Temer used that momentum to push through market-friendly though widely unpopular austerity reforms.
But as public opposition grew to the reforms, he ran out of steam. His signature attempt to strip down the hugely generous pension system has ground to a halt in Congress.
Now the truck strike has cast doubts over another of his liberal policies -- the 2016 decision to allow state-controlled oil company Petrobras to set fuel prices.
That decision led to today's high costs and the truckers' revolt. There are calls now on the enfeebled Temer not just temporarily to bring prices back down but to do away with Petrobras' autonomy altogether.
The oil company will be under renewed pressure starting Wednesday when workers are due to mount their own strike.
With Temer having staked his entire credibility on the economic reforms, he's now left looking helpless.
"He's lost the capacity to coordinate and to constructively intervene, as he could at the start of his rule, when he was seen as a successful reformer," said Carlos Pereira, at the Getulio Vargas Foundation university.
"The Temer government is moribund."