With Donald Trump now being the likely Republican Party (GOP) nominee, he will start to focus his attacks on likely Democratic nominee Hillary Clinton, slinging mud in her direction in what is sure to be a knock-down, drag out fight for the White House.

After Senator Ted Cruz and Ohio Governor John Kasich dropped out of the race after Trump's big win in Indiana Tuesday, Trump is the last Republican candidate standing in a primary season that started with a dozen candidates.

The New York real estate mogul, who just last summer was dismissed by pundits and political prognosticators as a flash in the pan, has steamrolled through several states and galvanized Republican rank-and-file voters like no other GOP candidate in years.

After virtually securing his nomination, Trump is now ready to focus on a single target, Clinton, who is his likely Democratic rival in the November general elections.

"Trump will begin attacking Hillary Clinton in earnest," Brookings Institution's senior fellow Darrell West told Xinhua. "He will call her 'corrupt Hillary' and knit together Benghazi, e-mail server, Whitewater, and her husband's infidelities into a narrative that seeks to make her unacceptable to American voters."

Indeed, Clinton has had her share of scandals over the years. More than two decades ago she was implicated in a failed land deal that became known as the "whitewater scandal."

While in Secretary of State, she was blasted for alleged incompetence for not providing better security for the US consulate in Benghazi, Libya, resulting in the 2012 terrorist attack that killed four Americans, including US ambassador Chris Stevens. Clinton has also taken heat for using a personal e-mail server while she was secretary of state, instead of a government server. Critics said she could have jeopardized national security, and a Justice Department investigation over the issue is ongoing.

Finally, Trump is sure to dredge up her husband's numerous marital infidelities, as former president Bill Clinton was known in the 1990s for his affair with then White House intern Monica Lewinsky, plus numerous other affairs.

In speeches and public appearances, Trump has already taken to referring to Clinton as "crooked Hillary" - a label intended to paint her as corrupt and dishonest.

"(Trump) will throw 100 pieces of mud against the wall, in hopes that something will stick and torpedo her candidacy," West said. "He will use the National Enquirer to leak unfounded stories against her," he said, speaking of a tabloid newspaper.

Clinton already has high negatives, but they are likely to increase due to the bruising campaign, he said.

While Trump will not soften his rhetoric on Clinton, he will make an effort to appear more presidential.

The brash businessman recently made a foreign policy speech that aspired toward a cogent argument but was widely slammed by foreign policy experts as incoherent and dangerous.

The author is a writer with the Xinhua News Agency. The article first appeared on Xinhua. opinion@globaltimes.com.cn