Hillary Clinton’s campaign is planning its most ambitious push yet into traditionally right-leaning states, a new offensive aimed at extending her growing advantage over Donald J. Trump while bolstering down-ballot Democrats in what party leaders increasingly view as a possible wave election.
Signaling extraordinary confidence in Mrs. Clinton’s electoral position and a new determination to deliver a punishing message to Mr. Trump and Republicans about his racially tinged campaign, her aides said Monday that she would aggressively compete in Arizona, a state with a growing Hispanic population that has been ground zero for the country’s heated debate over immigration.
Mrs. Clinton is “dramatically expanding” her efforts in Arizona, her campaign manager, Robby Mook, told reporters on Monday, pouring more than $2 million into advertising and dispatching perhaps her most potent surrogate, Michelle Obama, for a rally in Phoenix on Thursday.
In Indiana and Missouri, Mr. Mook said, the campaign will spend a total of $1 million to drive voter turnout, despite what he acknowledged as an “uphill battle” for Mrs. Clinton in two states with several competitive races below the presidential level.
“Donald Trump is becoming more unhinged by the day, and that is increasing prospects for Democrats further down the ballot,” Mr. Mook said. He predicted record turnout nationally, citing registration and early-voting data that exceed 2012 trends.
For weeks, Mrs. Clinton’s team has weighed how seriously to look beyond core battlegrounds like Pennsylvania, Florida and North Carolina, another state that Republicans carried in 2012.
Eager to torment Mr. Trump, and the Republicans straining to navigate his erratic bid, her team has also planned at least faint, attention-grabbing plays in other states with little history of Democratic success.
In Texas, the campaign has prepared an ad highlighting Mrs. Clinton’s endorsement from The Dallas Morning News. And Mrs. Clinton’s running mate, Tim Kaine, has begun sitting for local media interviews in Utah, where Mr. Trump has struggled to break away from Mrs. Clinton and an independent candidate, Evan McMullin, in recent polls. (On a conference call with reporters on Monday, Mr. Mook mentioned Mr. McMullin by name.)
The most brazen push, though, is in Arizona, where the campaign has also scheduled appearances on Mrs. Clinton’s behalf from her daughter, Chelsea, and Senator Bernie Sanders of Vermont.
“Donald Trump’s hateful rhetoric and deeply disrespectful remarks about Senator John McCain have made Arizona more competitive,” Mr. Mook said.
He added that Mrs. Clinton may appear there herself in short order. “We certainly hope to get her there,” he said.
The moves come as Mrs. Clinton has more conspicuously emphasized congressional and state races during campaign appearances, taking particular care to mention Senate and even House candidates on the stump and highlighting states that typically receive scant attention from Democrats.
“If you’ve got friends in Utah or Arizona, make sure they vote, too!” she told voters during a stop in Colorado last week. “We are competing everywhere.”
The campaign’s emphasis has strayed, at least somewhat, from its treatment of Mr. Trump and the wider Republican Party over the summer. During the Democratic convention and in the weeks that followed, Mrs. Clinton’s team sought to cast Mr. Trump as a menacing anomaly, at odds with the history of his party and its leaders.
More recently, as several Republican candidates have been forced into contortions — distancing themselves from Mr. Trump’s comments about women and the integrity of American elections, but often leery of renouncing their support outright — Mrs. Clinton and other Democrats have pounced.
“For months, G.O.P. members put their party ahead of the good of the country by refusing to take the step of condemning Donald Trump’s outrageous and insulting rhetoric,” Mr. Mook said. “Voters are now seeing through G.O.P. candidates who made last-minute conversions and tried to save themselves politically. And voters continue to be outraged that some of these candidates are choosing to stick with Donald Trump.”