Ted Cruz's conservative crusade for the US presidency is fighting for its life amid an Indiana vote that could effectively end the Republican primary season.
The fiery Texas senator hinted at an exit strategy, even as he vowed to compete to the end against surging party front-runner Donald Trump.
"I am in for the distance - as long as we have a viable path to victory," Mr Cruz told reporters after campaigning at a popular breakfast stop in Indiana.
With his supporters fearing Mr Cruz could lose a seventh consecutive state on Tuesday, the candidate's formulation hinted at a time when he may give up.
Like Ohio governor John Kasich, Mr Cruz is already mathematically eliminated from reaching a delegate majority before the Republican Party's national convention in July.
He retreated to Indiana more than a week ago, hoping a win could at least help him deny Mr Trump an outright primary victory and lead to a contested convention.
But a recent poll of likely Indiana voters showed billionaire Mr Trump holding a commanding lead.
Trump supporters confronted Mr Cruz at a stop in Marion, Indiana. "Lyin' Ted!" yelled one, using Mr Trump's pet name for his rival.
"What do you like about him?" Mr Cruz asked the man. "Name one thing."
"Everything," the protester replied.
After six straight victories across America's north east late last month, the maths and momentum are on Mr Trump's side.
The anti-Trump movement's only hope is to deny the businessman a 1,237-delegate majority by defeating him in Indiana and the handful of contests remaining over the next month. Then, Mr Cruz or another candidate would have to beat him when delegates gather in Cleveland, Ohio, in July.
"Millions of Americans are praying for this state," Mr Cruz said. "The entire country is depending on the state of Indiana to pull us back from this cliff."
Former reality television star Mr Trump sensed an Indiana knockout, telling a rally in Carmel: "Honestly, if we win Indiana, it's over. It's over. They're finished. They're gone."
Tuesday features a primary on the Democratic side, too. New signs emerged that front-runner Hillary Clinton's chief rival Bernie Sanders is fading as well.
Mrs Clinton announced $26m in new fund raising in April, narrowly beating Mr Sanders. His total of $25.8m last month marked a steep decline from the $46m he collected in March.
Mr Sanders also refused to report how much money he had in the bank, raising questions about whether he can sustain his online fund-raising dominance as his path to the nomination becomes less likely.
Shrugging off the numbers, Mr Sanders, like Mr Cruz, vowed to "fight hard as hard as we can for every vote".
He called the Democratic primary process "rigged", noting that he has won 45% of the pledged delegates awarded after primaries or caucuses, but only about 7% of superdelegates, the Democratic officials and party leaders who can support the candidate of their choice.
Still, he showed no signs of letting up on Mrs Clinton, pointing to differences with the former US secretary of state over fund raising, Goldman Sachs speeches, the Iraq war, fracking and the minimum wage.
Polls show a close vote is likely.
Mr Cruz barnstormed Indiana with five stops on Monday alone in a desperate sprint for support alongside his latest high-profile supporter, Indiana governor Mike Pence.
"We need every single vote," he declared at Bravo Cafe in Osceola, where he predicted a tight finish the next day.
Mr Trump led by 15 points in an NBC News/Wall Street Journal/Marist poll conducted last week, even after Mr Cruz took extraordinary steps to boost his chances in the state.
He announced his pick for vice president last week, unveiling former businesswoman Carly Fiorina as his running mate at an Indiana stop that appeared rushed. Days earlier, he declared alliance of sorts with Mr Kasich in which the Ohio governor agreed to pull his advertising from Indiana airwaves.
The strategy seemed to unravel even as it was announced. And it may have backfired. The NBC poll found nearly six in 10 Indiana primary voters disapproved of the Cruz-Kasich arrangement.
Mr Trump's advantage comes even as he is getting badly outspent on advertising in the state.
He has spent about $1m on ads over Indiana airwaves, while Mr Cruz's campaign, pro-Cruz super PACs and anti-Trump groups have combined for about $6.4m, according to data from Kantar Media's Campaign Media Analysis Group.
On the Democratic side, Mrs Clinton's campaign has not dropped a dollar on television or radio advertising in Indiana. Mr Sanders has spent $1.8m.
Mr Trump, for his part, held a pair of rallies in the state on Monday. But with an overwhelming delegate lead, he signalled it was only a matter of time before he clinches the Republican nomination even if he stumbles on Tuesday.
"We'll win it next week or the week after or the week after, and it's fine, because they have no path and I have an easy path," he said.