WASHINGTON: Months of intense focus on the Republican race — and front-runner Donald Trump — have reverberated through the Democratic field, prompting front-runner Hillary Clinton to turn her attention to her would-be Republican challengers and leaving her chief rival, Vermont Sen. Bernie Sanders, gasping for airtime.

Now, after spending weeks largely out of the spotlight, Clinton plans to intensify her campaign schedule from an almost incumbent-style effort to a more aggressive, first-timer approach.

With just six weeks left before the first round of primary voting, Clinton plans a series of multi-day swings through Iowa starting in January, interspersing trips there with stops in New Hampshire and other early voting states. Her campaign will also unveil what Clinton has called her "not-so-secret weapon," sending her husband, former President Bill Clinton, out to hit the stump after months of behind-the-scenes activity, wooing donors in private events.

And in a sign of the escalating battle between the two party front-runners, her campaign was forced to engage with Trump on Tuesday after he called Clinton's bathroom break during Saturday's Democratic debate "disgusting" and said she was "schlonged" in the 2008 race for the Democratic nomination, using a vulgar Yiddish term to describe her loss to now-President Barack Obama. On Twitter Tuesday, Trump denied the word was vulgar and said it simply means "beaten badly."

In Iowa on Tuesday, Clinton said: "It's important to stand up to bullies wherever we are and why we shouldn't let anybody bully his way into the presidency. Because that is not who we are as Americans."

Though Clinton leads Sanders in national polls by more than twenty percentage points, the numbers are much tighter in Iowa and New Hampshire, where the Vermont senator has an edge. The Sanders campaign believes victories in those two states would undercut Clinton's strength and send him into the next contests — in Southern and Western states where he's polling lower— with a boost of momentum and a path to victory in the nomination battle.

But Sanders is struggling to find his footing as the race has shifted away from his core economic message about income inequality to one of national security after terrorist attacks in Paris and San Bernardino, California.

Clinton aides say they are taking nothing for granted in the upcoming contests.

In recent weeks, however, Clinton has spent far more time attacking Trump and her would-be Republican rivals than Sanders, demonstrating a growing confidence in her primary standing and increased focus on the general election.

Democratic leaders believe that reminding their voters of whom they may be up against in November helps motivate their party in a primary that hasn't generated the excitement of the Republican field.

"I want him to talk every single day," Democratic National Committee chairwoman Debbie Wasserman Schultz said of Trump. "It's going to help propel our nominee to the White House."

For Clinton, going after Trump creates an opportunity to re-enter a political conversation that has largely moved away from the Democratic side and strike back at her Republican opponents, who are getting plenty of airtime to lob attacks not only at each other but Clinton as well.

"He's the leading Republican candidate but he's not really all that different from the other Republican candidates," said Clinton campaign chairman John Podesta. "He heats things up more and that's not only outrageous but it's dangerous."

But even as Clinton and her party publicly slam Trump, they're quietly grappling with the question of how to target the Republican front-runner without discounting the feeling of insecurity he's tapped into in the electorate.

Between attacks on what she calls his bigoted rhetoric and proposal to ban Muslims from entering the US, Clinton has also begun telling voters that "it's OK to be afraid."

The lack of attention on the Democratic race has given Clinton a break from the intense scrutiny she faced in the summer, when much of the political conversation was focused on her use of a private email server as Secretary of State and the foreign financial ties of the Clinton Foundation, the non-profit started by her husband.

Her campaign has been able to use the lull to build up its operation, organize key states, promote celebrity endorsements and roll out policies on foreign policy, infrastructure, manufacturing and taxes. She's done a number of interviews on late night and afternoon TV talk shows designed to show off her softer side, including a well-received cameo on "Saturday Night Live."

"We're the sideshow," said Paul Maslin, a Democratic pollster unaffiliated with either campaign. "This is the opportunity to start to lay the groundwork for a general election message."