The president is expected to meet survivors of Hurricane Harvey and to witness first-hand the devastation that has presented a major test for his administration.
He will have to navigate not just receding flood waters but perilous political currents similar to those which damaged Bush in the wake of Hurricane Katrina in 2005.
Melania Trump is accompanying her husband in what aides hope will be a gaffe-free inspection of relief efforts in Houston and further up the Gulf coast at Lake Charles, Louisiana.
Trump set the stage on Friday by signalling a request to Congress for a $14.5bn down payment for storm victims and a declaration making Sunday a national day of prayer.
Flanked in the Oval office by leaders from the American Red Cross, the Salvation Army and Southern Baptist Disaster Relief, the president invited all Americans “to join us as we continue to pray for those who have lost family members or friends, and for those who are suffering in this time of crisis”.
The sombre tone contrasted with campaign-style rhetoric about crowd size during his visit to Texas earlier in the week, as well as tweets marvelling at the storm’s power, which had prompted accusations that Trump was temperamentally unfit for the role of consoler-in-chief.
In addition to projecting empathy on Saturday, Trump must manage a tangle of hurricane-related consequences which complicate his fiscal, immigration and border security policies.
The scale of the disaster loomed clearer on Friday as rescuers worked their way through the 300-mile swath of south-east Texas drenched by Harvey. Some communities remained submerged; others lacked water and power. Texas officials estimate more than 185,000 homes were damaged and 9,000 destroyed. The Red Cross said 42,000 people were in shelters. At least 45 people died.
A category 4 hurricane when it made landfall last week, Harvey still packed a wallop as a tropical depression as it moved north-east, triggering flood warnings in Kentucky and Tennessee.
Trump has given an uneven response to the first national disaster of his presidency.
Last week, he swiftly granted the Texas governor Gregg Abbott’s request for a disaster declaration, releasing federal funds, and has remained in close contact with state officials.
Brock Long, his pick to run the Federal Emergency Management Agency (Fema), has proved capable, according to analysts.
The $14.5bn request to Congress – $7.8bn to be released in coming days, the rest at the end of the month – will cheer state officials who hope to eventually gain $120bn in federal help.
But as the storm barrelled in last week, Trump struck discordant notes.
“Wow – Now experts are calling #Harvey a once in 500 year flood!” he tweeted, sounding more awed than horrified. “125 MPH winds!”
He pardoned Joe Arpaio, a controversial former sheriff, in the early hours of the storm. Asked about timing, Trump said television ratings would be higher than normal.
The former Celebrity Apprentice host also noted that Long, the Fema chief, had “become very famous on television over the last couple of days”.
And on a visit to Corpus Cristi and Austin on Tuesday, he seemed more excited than sympathetic, telling a rally: “What a crowd, what a turnout.”
Critics complained that his subsequent tweet – “After witnessing first hand the horror & devastation caused by Hurricane Harvey, my heart goes out even more so to the great people of Texas!” – was false because he did not personally witness storm damage nor meet any victims.
Houston, which bore the brunt of Harvey’s wrath, will give the president ample opportunity to do both. He is also expected to meet the mayor, Sylvester Turner, a Democrat who has vowed to personally defend undocumented immigrants from any Trump-inspired crackdown.
The storm has complicated Trump’s agenda in Washington.
Massive federal aid for Texas and Louisiana will undermine efforts by the White House and congressional Republicans to curb the deficit.
But administration officials have refused to back away from the president’s threat to stake government operations on funding for what was arguably his most signature campaign promise.
“The president’s very much committed to building the wall,” the White House press secretary, Sarah Huckabee Sanders, told reporters Friday when asked if Trump was willing to withdraw the threat of a government shutdown over the project.
The president faces an additional dilemma over whether to accept an offer of aid from Mexico, his favourite punching bag. Abbott said he would accept.
Harvey also put Trump’s denial of climate change under fresh scrutiny. Experts said global warming aggravated the storm.
Trump’s overriding political challenge in Houston and Louisiana, however, will be to not resemble Bush in the wake of Katrina. Bush appeared slow to respond, detached from the suffering and deluded in his confidence in Michael Brown, the hapless head of Fema in 2005. “Brownie, you’re doing a heck of a job,” said Bush, misplaced praise which haunted the rest of his presidency.
On the eve of Harvey making landfall, the Republican senator Chuck Grassley tweeted a warning to Trump to not repeat Bush’s errors. The president tweeted back: “Got your message loud and clear. We have fantastic people on the ground, got there long before #Harvey. So far, so good!”
