Hillary Clinton’s Democratic rivals took it easy on her during their first presidential debate last month, but with the Iowa caucus now less than three months away and polls trending in the front-runner’s direction, Bernie Sanders and Martin O’Malley won’t be so kind when they meet on the debate stage later in Des Moines this week.

Since the Las Vegas debate, Sanders has adopted a more aggressive stance toward the former secretary of state, pointing out their differences with little ambiguity.

“For me-as opposed to some other unnamed candidates-the issue of Keystone was kind of a no-brainer,” he said Friday, typifying his approach to Clinton, at a South Carolina forum where all three candidates appeared for one-on-one interviews with MSNBC’s Rachel Maddow.

O’Malley’s moment

Looking to expand his influence in what’s now a three- person field, O’Malley has signaled that he will take on a sharper edge against Clinton and Sanders alike when he joins them at Drake University on Saturday night.

“I am a Democrat. I’m a lifelong Democrat. I’m not a former independent. I’m not a former Republican,” he said at Friday’s forum, taking swings at Sanders and Clinton, who was a member of the GOP when she started college.

Like Sanders, O’Malley plans to keep reminding voters of the issues on which Clinton has been slow to embrace positions favored by the left wing of the party. “On critical issues where Governor O’Malley has led-like the death penalty, gun safety, or immigration reform, there are clear differences,” said Haley Morris, an O’Malley spokeswoman.

Clinton’s strategy

Clinton, meanwhile, is likely to do just as she did at Friday’s forum, aiming to stay above the fray and showing no sign of being intimidated by her opponents. Clinton looks for opportunities “to talk not just about policy but demonstrate that she really understands the problems are in peoples’ lives,” her communications director, Jennifer Palmieri, said after the forum, likely foreshadowing how she’ll respond to Saturday’s debate. “It seemed like the other candidates wanted to accomplish something else. And we didn’t feel the need to do that.”

She is, though, subtly shifting slightly left on some issues so as to not be the outlier in the Democratic field. On Saturday, at a town hall for black voters in Orangeburg, South Carolina, Clinton told host Roland Martin that she supports reclassifying marijuana as a Schedule II drug so that more research can be conducted on its benefits. Sanders, who like Clinton opposes the current classification of marijuana as a more-dangerous Schedule I drug, wasn’t satisfied by the announcement, saying that “her approach ignored the major issue,” which is that the reclassification would still make marijuana a federally regulated substance, a practice for which he’s proposed legislation to end.

Sanders seeks the right tone

At times, Sanders has stumbled to find the right tone when talking about Clinton, intentionally or not. After Clinton suggested that his assertion during the debate that Americans needed to “stop shouting” about gun laws was a sexist one, Sanders had to make clear that it was a line he’d been using for months to sum up the national debate over the Second Amendment.

His efforts to be bold have occasionally gone a bit too far, as they did when he told the Boston Globe editorial board last week “I disagree with Hillary Clinton on virtually everything” only to walk it back. “We have very significant differences, and the key difference is I see a nation in which we have a grotesque level of income and wealth inequality,” he said Sunday on ABC’s This Week.

“I think on issues, for example, like Wall Street-you know, I believe that these guys who drove our economy into the ground, destroyed so many lives,” he said Sunday. “I think that at the end of the day, what we have to do is re-establish Glass- Steagall, we have to break up these huge financial institutions. That is not Hillary Clinton’s position at all. You know, I was there on the [Trans-Pacific Partnership] from way back, that was-Hillary Clinton took a little while to get there.”

During his speech at the Iowa Jefferson-Jackson Dinner late last month, his argument against Clinton hinged on his argument that he’d taken positions on several key issues first only to watch his opponent get to the same place, years or even decades later. “I will govern based on principle, not poll numbers,” he said then, in a nod to one of Clinton’s perceived weaknesses that had also been at the core of the breakout speech that then- Sen. Barack Obama gave at the same dinner in 2007. His campaign did not respond Sunday to requests for comment.

Gloves could come off

For months on the campaign trail ahead of the first debate, O’Malley threw more than a few elbows at Clinton and Sanders alike. But held back once he was sharing a stage with them, in part because he knew his appearance would be many Americans’ first introduction to him. Taking the stage before them at Friday’s forum in South Carolina, he showed that his approach is changing.

“When President Obama was running for reelection, I was glad to step up and work very hard for him, while Senator Sanders was trying to find someone to primary him,” he said Friday, referring to Sanders’s suggestion in a 2011 interview that “it would be a good idea if President Obama faced some primary opposition.” It was a charge O’Malley has made in recent weeks on the trail in Iowa but had never before pushed in front of a national audience or the national media. (Sanders fought back later in the weekend, telling ABC that the claim was “categorically false,” though some who worked on Obama’s campaigns say Sanders was never particularly helpful to the president.)

O’Malley also made a generational argument on Friday, telling reporters gathered in the spin room after the forum that voters have a “pretty clear choice between the three alternatives … two of them from our party’s rather divided past. And one of us-namely me-who can actually bring people together to get things done.”

On the attack

On Sunday, in a speech in Las Vegas, O’Malley charged that “when you listen to the two of them talk about immigration, you can tell they are very much of yesterday’s mindset.” He also chastised Clinton for approaching policy with “poll-tested triangulation.”

His campaign, meanwhile, attacked Clinton for choosing not to attend the event where he spoke, Fair Immigration Reform Movement Presidential Forum, which Sanders is addressing on Monday. “This is the latest in a string of immigration forums that she has refused to attend during this campaign,” O’Malley spokeswoman Gabriela Domenzain said in a statement. “At this point, it should not come as any surprise why she continues to dodge having a meaningful conversation with the new American immigrant community.”

Clinton will instead be in New Hampshire on Monday and Tuesday, filing paperwork to get on the state’s primary ballot and appearing at events focused on veterans, the environment and business.

Still, attacking Clinton on the debate stage is a risky strategy that could backfire. Her national approval rating among Democrats was 79 percent in an ABC News/Washington Post poll conducted before last month’s debate and Benghazi testimony, and is at similar levels in Iowa and New Hampshire. And so, while their gloves may be off, in the parlance of campaign reporters, her opponents are pulling their punches.

“On her worst day, Hillary Clinton will be an infinitely better candidate and president than the Republican candidate on his best day,” Sanders said Sunday on ABC.