Red state Democratic Sen. Claire McCaskill faces Trump barrage as she opposes Kavanaugh nomination

• Sen. Claire McCaskill opposes President Donald Trump's Supreme Court nominee Brett Kavanaugh, as the president heads to her state for a rally on Friday.
• Trump will rally in Missouri for state Attorney General Josh Hawley, who is challenging McCaskill in one of the year's most important Senate races.
• Trump will likely hammer McCaskill over her decision, though voters in the state appear to care more about health care than the Supreme Court.

Brendan Smialowski | AFP | Getty Images

President Donald Trump (R) listens while US Senate candidate from Missouri Josh Hawley (L) speaks at the Veterans of Foreign Wars of the United States National Convention July 24, 2018 in Kansas City, Missouri.

Sen. Claire McCaskill's fight for her political life just got more complicated.

The Missouri Democrat said Wednesday she will oppose President Donald Trump's Supreme Court nominee Brett Kavanaugh. McCaskill, deadlocked in her re-election bid in a state where the president triumphed in 2016, also voted against Justice Neil Gorsuch's confirmation last year.

McCaskill's stated opposition to Kavanaugh hands more fodder to Republicans in the red state, who have already hammered the senator over her reluctance to openly support him. The president heads to Missouri on Friday, when he will likely slam McCaskill for her vote as he rallies support for her challenger, Missouri's GOP Attorney General Josh Hawley.

McCaskill tweet

McCaskill, saying Kavanaugh will boost the influence of wealthy donors in elections, became the first of the five most vulnerable Senate Democrats to oppose Trump's choice. The GOP onslaught against McCaskill foreshadows what her four colleagues running in states Trump won easily could face in the six weeks before November if they join her in opposing Trump's court pick.

Hawley and national Republicans pounced on McCaskill's decision. The state attorney general called her a "Washington liberal" and questioned her reasoning, arguing the senator has not shared enough about her own family's finances. The National Republican Senatorial Committee, the Senate GOP's campaign arm, also contended McCaskill's move shows she has moved too far to the left.

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A sexual assault allegation against Kavanaugh — which McCaskill said her "decision is not based on" — has thrown his confirmation into doubt. The accusation, which the federal appeals judge denies, dominated conversation in Washington and on cable news this week as Republicans try to confirm him before the midterms. Hawley supports Kavanaugh's confirmation and wants both him and his accuser, California college professor Christine Blasey Ford, to testify.

Despite the GOP's attacks over McCaskill's Supreme Court vote, some in Missouri say it will have limited effect on her push for re-election in November.

"I am skeptical that many votes hinge on Senator McCaskill's stance on Kavanaugh, one way or the other," Peverill Squire, a political science professor at the University of Missouri, wrote to CNBC. "While his nomination has consumed Washington, it does not appear to be a central issue for most Missourians."

The senator's decision on Kavanaugh had nothing to do with her re-election bid, McCaskill's campaign said. In addition, her campaign noted that polling in Missouri generally shows voters care most about health care. McCaskill has slammed Hawley on the issue, as he joined other state attorneys general in signing on to a lawsuit challenging pre-existing conditions coverage under the Affordable Care Act.

Bill Clark | CQ Roll Call | Getty Images

Sen. Claire McCaskill, D-Mo.

Other surveys suggest voters may not care all that much about Kavanaugh getting confirmed. Opposition to the appeals judge rose among registered voters nationally in the last month following his confirmation hearings and the assault allegation, according to an NBC News/Wall Street Journal poll released Thursday. Only 34 percent of voters want him on the top U.S. court, versus 38 percent who oppose his confirmation, it found.

Another factor plays in McCaskill's favor. Forty-five percent of Missouri likely voters approve of the job Trump is doing as president, while 46 percent disapprove, according to a recent NBC News/Marist poll. The president's reception there appears to have dipped since 2016, when he carried the state by nearly 20 percentage points.

Of course, Democrats running in states Trump won with an even wider margin face a worse political dilemma than McCaskill as they try to tout bipartisan credentials. In West Virginia, Trump triumphed with a more than 40-point victory, while he carried North Dakota by more than 30 points.

Factors outside of the Democrats' control may drive their decisions on Kavanaugh. His nomination will only fail if two Republicans oppose him. Therefore, if all GOP senators indicate they will back him, some Democrats may join them in order to hedge their political bets. Such a move would also risk angering Democrats in their states.

Trump is unlikely to forget about the Supreme Court when he campaigns for Republican Senate candidates in the coming weeks. He mentioned Kavanaugh multiple times as he rallied for Sen. Dean Heller, R-Nev., in Las Vegas Thursday night. Heller is the most vulnerable Senate Republican this year.

"We got Gorsuch. ... We're going to get Brett. I have very good people," Trump said at the rally.

Pivotal Missouri race is neck and neck

Trump's visit to Missouri comes as McCaskill and Hawley jockey for position in what, by all accounts, looks like a deadlocked race. The NBC/Marist poll found the candidates tied at 47 percent of support from likely voters in a head-to-head matchup.

With Libertarian Party candidate Japheth Campbell and Green Party candidate Jo Crain included, it found a 4 percentage point edge for McCaskill. Ten percent of likely voters said they might support a different candidate on Election Day. Most other polls show a dead heat in Missouri, as well.

McCaskill had a clear fundraising advantage over Hawley as of July 18. Her campaign had $6.6 million on hand, versus $2.3 million in the bank for Hawley, according to Federal Election Commission records.

Hawley has received slightly more of a boost from outside groups than his opponent. Those organizations have spent more than $16 million opposing McCaskill, while outside groups have shelled out nearly $14 million against Hawley.

Both McCaskill's campaign and outside groups supporting her, including the pro-Democratic Senate Majority PAC, have focused primarily on health care. They have targeted the Hawley-backed pre-existing conditions lawsuit.

"Health care, particularly concerns about pre-existing conditions protections, is probably the best weapon McCaskill has to use against Hawley," the University of Missouri's Squire said. "Hawley's campaign has yet to offer a convincing counter to the many ads being run against them on pre-existing conditions protections."

Hawley says he wants to shield pre-existing conditions coverage despite the litigation.

"Senator McCaskill would have you believe that the only way to cover pre-existing conditions is to keep all the failures of Obamacare," he said in a statement last week. "That's simply not true. I'm committed to covering those with pre-existing conditions, and we don't have to break the Constitution to do it."

The state attorney general, meanwhile, has focused more on McCaskill's character. He has cast the senator as a wealthy Washington elite who has not showed enough transparency about both her personal finances and political backers.

That strategy partly drove his response to McCaskill's Supreme Court vote, in which he contended the senator "runs her family business as a dark money operation."

While super PACs have supported McCaskill's re-election, the senator's campaign says she supports a constitutional amendment to overturn the Citizens United Supreme Court decision and other proposals meant to restrain the influence of money in politics. The Citizens United ruling found that political spending is a form of protected speech, which therefore gives corporations and unions more leeway to influence elections.

Many Democrats believe Kavanaugh, as a Supreme Court justice, would rule on cases in a way that further boosts the reach of money in politics.

A White House spokesman overseeing communications for Kavanaugh did not immediately reply to CNBC's request for comment.

— CNBC's Christina Wilkie contributed to this report.

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