Former President George W. Bush has refused to endorse Republican nominee Donald Trump, and also has refrained from criticizing him.
But while he still has not done so by name, the former president rebutted many of Trump's foreign policy stances at a fundraiser in Cincinnati for Sen. Rob Portman, R-Ohio, according to a report in The Wall Street Journal.
Bush, without directly framing his comments in the context of the 2016 presidential race, denounced the "isolationism, nativism and protectionism" that have been part of Trump's campaign message, the Journal said, citing four of the fundraiser's attendees.
See George W. Bush and Jeb Bush through the years:
Jeb and George Bush through the years
Jeb and George Bush through the years
** FILE ** President George W. Bush, center, walks off the 18th hole with his brother, Florida Gov. Jeb Bush, right, and father, former President George Bush, left, at the Cape Arundel Golf Club in Kennebunkport, Maine, in this July 7, 2001 file picture. Could there be a third President Bush? The current chief said Wednesday May 10, 2006 that younger brother Jeb would make a great one, too, and has asked him about making a run. The first President Bush likes the idea as well. (AP Photo/J. Scott Applewhite)
President Bush, center, with former President George H.W. Bush, left, and Florida Gov. Jeb Bush, walk together after participating in the christening ceremony of the aircraft carrier George H.W. Bush in Newport News, Va., Saturday, Oct. 7, 2006. (AP Photo/Lawrence Jackson)
Florida Gov. Jeb Bush, left, listens as former President George H. W. Bush offers condolences to the Ford family during a news conference in remembrance of former President Gerald R. Ford at the Gasparilla Inn in Boca Grande, Fla., Wednesday, Dec. 27, 2006. (AP Photo/Armando Solares)
President Bush waves to the crowd with his wife, Laura, and brother Jeb Bush on Monday, Nov. 6, 2006, in Pensacola, Fla., where Bush was drumming up support for local Republican candidates. (AP Photo/Mari Darr~Welch)
President Bush, left, stands on stage with his brother Gov. Jeb Bush, right, at a campaign rally at Pensacola Civic Center, Monday, Nov. 6, 2006. in Pensacola, Fla. (AP Photo/Pablo Martinez Monsivais)
President Bush, left, spends a moment with his brother and Florida Gov. Jeb Bush, prior to the President's speech on Social Security at the Pensacola Junior College, Friday, March 18, 2005, in Pensacola, Fla. (AP Photo/Phil Coale)
President George Bush chats with brother Gov. Jeb Bush as they acknowledge cheering supporters at a fundraiser for the Republican Party of Florida at the Contemporary Resort at Disney World in Orlando, Florida, Friday, February 17, 2006. (Photo by Joe Burbank/Orlando Sentinel/MCT via Getty Images)
Texas Gov. George W. Bush, right, gestures as his brother Florida's governor-elect Jeb Bush looks on during a joint news conference in New Orleans Wednesday, Nov. 18, 1998. The Bush brothers are attending the Republican Governors Association meeting which runs through Friday. A flood of media requests to interview the Texas governor and the Florida governor-elect prompted the sons of former President Bush to schedule a news conference Wednesday. (AP Photo/Bill Haber)
Florida Gov. Jeb Bush, right, hugs his brother, President Bush, left, after introducing him at a campaign rally at Pensacola Civic Center in Pensacola, Fla., Monday, Nov. 6, 2006. (AP Photo/Pablo Martinez Monsivais)
President Bush jokes with his brother Florida Gov. Jeb Bush on Monday, Nov. 6, 2006, in Pensacola, Fla., where Bush was drumming up support for local Republican candidates. (AP Photo/Mari Darr~Welch)
Former U.S. President George H. W. Bush, center, is joined by his sons, former U.S. President George W. Bush, left, and former Florida Gov. Jeb Bush, as he speaks to reporters after his parachute jump with the Army Golden Knights parachute team to celebrate his 85th birthday, Friday, June 12, 2009, in Kennebunkport, Maine. (AP Photo/Robert F. Bukaty)
President Bush greets his brother,former Florida Gov. Jeb Bush, right, and Jeb's son, George P. Bush, left, as he arrives at Palm Beach International Airport in West Palm Beach, Fla., Tuesday, March 18, 2008. (AP Photo/Gerald Herbert)
President George H. W. Bush, left, with his son former Florida Gov. Jeb Bush, right, enters the West Wing of the White House to meet with President Barack Obama Saturday, Jan. 30, 2010, in Washington. (AP Photo/Alex Brandon)
President George W. Bush, left, smiles while being introduced by his brother Florida Gov. Jeb Bush, right, at the Florida Victory 2004 rally on Sunday, Oct. 31, 2004 in Tampa, Fla. (AP Photo/Scott Audette)
This photo taken Feb. 15, 2011, show former Florida Gov. Jeb Bush greeting his mother, former first lady Barbara Bush, at the White House's 2010 Presidential Medal of Freedom ceremony in Washington, where her husband, former President George H.W. Bush is to receive the Medal. Jeb Bush has already heard his mother, Barbara, tell everyone âweâve had enough Bushesâ in the White House. In the lead-up to 2016 presidential campaign, the former Florida governor says heâs in his 60s and doesnât have to do everything his mom says. âI'm trying to avoid the family conversation,â he said. (AP Photo/Carolyn Kaster, File)
In this Oct. 22, 2002, file photo former first lady Barbara Bush makes a point as she campaigns for her son, Florida Gov. Jeb Bush, at Nova Southeastern University in Davie, Fla. Amid the celebration surrounding the opening of son George W. Bush's presidential library, Barbara Bush is brushing aside talk of her son Jeb running for president in 2016. When asked how she felt about it she told NBC's "Today" show, Thursday, April 25, 2013, "We've had enough Bushes." (AP Photo/Marta Lavandier, File)
Florida Gov. Jeb Bush, right, reaches out to grab his brother President George W. Bush before a speech Friday morning March 8, 2002 at America II Electronics in St. Petersburg, Fla. In the his remarks, Bush said he does not know whether Osama bin Laden is dead or alive but cautioned Americans against judging the success of the war on the fate of the terrorist mastermind. (AP Photo/Chris O'Meara)
Former first lady Barbara Bush laughs with her son, Florida Gov. Jeb Bush, during a campaign stop in Ellenton, Fla., Monday, Oct. 30, 2000. The two were campaigning for another of her sons, Republican presidential candidate Texas Gov. George W. Bush. (AP Photo/Chris O'Meara)
Republican presidential candidate Texas Gov. George W. Bush jokes with his brother, Florida Gov. Jeb Bush, left, during a bus ride to a rally at Florida International University in Miami, Fla., Sunday, Nov. 5, 2000. At left is New York Mayor Rudolph Giuliani. (AP Photo/Eric Draper)
Texas Republican Gov. George W. Bush, right, and Florida's Governor-elect, Jeb Bush, answer questions at a news conference in New Orleans Wednesday Nov. 18, 1998. A flood of media requests to interview the Texas governor and the Florida governor-elect prompted the sons of former President Bush to schedule a news conference. The governors are attending the Republican Governors Association. (AP Photo/Bill Haber)
Florida Gov.-elect Jeb Bush, left, laughs during a joint news conference in New Orleans Wednesday, Nov. 18, 1998, with his brother Texas Gov. George W. Bush. The Bush brothers are attending the Republican Governors Association meeting which runs through Friday. A flood of media requests to interview the Texas governor and the Florida governor-elect prompted the sons of former President Bush to schedule a joint news conference. (AP Photo/Bill Haber)
Former President George Bush, right, clenches his fist Sept.16, 1994 as he hugs son, Jeb during a Florida GOP fund-raiser in Tampa. After a hiatus, Bush has been hitting the campaign trail and lecture circuit with a vengence, raising millions for Republican candidates and getting digs in at President Bill Clinton along the way. (AP Photo/Chris O'Meara)
Former President George H. W. Bush, right, and son Jeb Bush chat with recruits at the Pinellas County jail's boot camp in St. Petersburg. FL., March 28, 1994. Jeb Bush, who is running for the Republican nomination for governor, was on a campaign swing with his father. (AP Photo/Peter Cosgrove)
Cheerleaders shout their encouragement as Florida Republican gubernatorial candidate Jeb Bush and former President George Bush applauds Barbara Bush, center, during her address to a rally on Oct. 10, 1994 at Church Street Station in Orlando, Florida. Jeb Bush is running for governor against incumbent Democrat Gov. Lawton Chiles. (AP Photo/Peter Cosgrove)
President George H. W. Bush talks with his son Jeb, during a round of golf at the Cape Arundel Golf Club in Kennebunkport ME., Aug. 27, 1990. The president is scheduled to meet with Canadian Prime Minister Brian Mulroney Monday, at his Walker's Point home. (AP Photo/Doug Mills)
MACDILL AIR FORCE BASE, UNITED STATES: US President George W. Bush (R) reaches out to shake hands with his brother Florida Governor Jeb Bush (L) shortly after Air Force One arrived at MacDill Air Force Base, Florida, 09 May 2006. AFP Photo/Paul J. Richards (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)
Washington, UNITED STATES: US President George W. Bush (L) looks on as his brother Florida Governor Jeb Bush speaks 19 April, 2006. Governor Bush was among several governors who met with the president after an Easter trip to Iraq, Afghanistan and Kuwait. AFP PHOTO/Jim WATSON (Photo credit should read JIM WATSON/AFP/Getty Images)
President George Bush (left) and brother Gov. Jeb Bush acknowledge cheering supporters at a fundraiser for the Republican Party of Florida at the Contemporary Resort at Disney World in Orlando, Florida, Friday, February 17, 2006. (Photo by Joe Burbank/Orlando Sentinel/MCT via Getty Images)
ST. PETERSBURG, FL - OCTOBER 19: U.S. President George W. Bush (L) and his brother Florida Governor Jeb Bush (R) smile while greeting supporters during a campaign rally at Progress Energy Park October 19, 2004 in St. Petersburg, Florida. Recent polls indicate Bush is maintaining a slight lead over his Democratic challenger U.S. Sen. John Kerry (D-MA). (Photo by Mark Wilson/Getty Images)
PARK CITY, UT - JANUARY 22: Jeb Bush is seen at Salt Lake City Airport on January 22, 2015 in Park City, Utah. (Photo by JOCE/Bauer-Griffin/GC Images)
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"It was an interesting exercise of statecraft," former Ohio Secretary of State Ken Blackwell told the Journal. "No one could say he directly spoke in attack mode against Donald Trump. Neither could anybody miss the fact that he thought there were some cutting-edge issues that Trump is advancing that need to be scrutinized and debated."
For example, attendees reported that Bush said Muslim women should travel to the U.S. so they can encourage their home countries to emulate America's free society and bring equality to the Middle East. Trump, meanwhile, has floated the idea of restricting Muslims from entering the U.S.
Bush "said everyone wants to be free," U.S. Rep. Brad Wenstrup of Cincinnati told the Journal. "He really touched everyone in the room."
Although they did not openly oppose Trump's nomination, the Bushes have declined to endorse Trump or any candidate in the 2016 race – a remarkable snub in that the Republican Party's most recent presidents are refusing to back their potential successor.
Portman, meanwhile, has labored to walk the line between supporting his party's nominee, having endorsed Trump but avoided campaigning with him thus far. Locked in a tight re-election battle with former Ohio Gov. Ted Strickland, Portman has taken pains to draw sharp differences with the GOP nominee, but has nonetheless come under fire for continuing to support him.
"If there is a shred of sincerity behind Portman's statement, he would show the same kind of courage that Republican Gov. [John] Kasich has and retract his endorsement of Trump today," a Strickland spokesman said in a statement Monday, after Portman distanced himself from Trump's critiques of Khizr and Ghazala Khan, the Muslim-American parents of a soldier killed in Iraq.
Portman, who served as U.S. trade representative and director of the Office of Management and Budget in Bush's administration, is considered one of the most vulnerable incumbents up for re-election in the Senate this fall.