GOP senators already miss Gary Cohn

"When it came to economic issues -- and, to be frank, even beyond -- he was our security blanket," one senior Republican aide said, pointing to active back channels between Capitol Hill and Cohn on policy issues, and a willingness, whether real or perceived, to effectively present congressional GOP concerns to a president whose policy positions and governing style many walking the halls of the Capitol still haven't quite figured out.

Not even a week after Trump announced he was slapping new tariffs on aluminum and steel, Hill Republicans have lost a once unlikely but key ally in the White House. Cohn, a registered Democrat, had become an invaluable asset for congressional Republicans, helping usher through the party's massive tax package last year and serving as an economic liaison to a White House that some on Capitol hill have found to be chaotic, divided and hard to predict at times.

The loss of Cohn has left Republicans openly questioning whom they can count on in a White House that seems to be hemorrhaging staff, especially on an issue like trade, where the protectionist wing of Trump's orbit appears to be winning the day.

There's no shortage of acknowledged irony in what by Wednesday appeared to be a mix of disappointment and borderline emotional longing for the continued presence of a man who joined the administration as a political neophyte and with public ties to the opposite party -- one with extensive New York City and Goldman Sachs lineage, no less.

Asked who would fill the void on trade in Cohn's absence, Sen. John Thune of South Dakota, a member of GOP leadership, offered a sigh.

"That's a good question. Kelly's probably our best shot, I suppose," Thune said noting also members of the Cabinet who shared the mainline GOP view on trade. "In terms of that immediate circle in the White House, Cohn was sort of that guy that was the voice of reason, so I'm concerned about who's going to be in the President's ear."

During a GOP lunch Wednesday, multiple senators told CNN that Cohn's departure was a topic of conversation as lawmakers grappled with how they'd deal with Trump's impending trade announcement.

"I can't tell you that anything was resolved, rather that it was just being discussed," said Sen. Bill Cassidy, a Republican from Louisiana.

Top Senate Democrat Chuck Schumer of New York said Wednesday that the White House was being "hollowed out."

"One of the problems here is that the White House is getting hollowed out and the number of people capable of doing things, doing real things -- whether you agree or disagree ideologically -- is getting smaller and smaller," Schumer said. "And they are unable to recruit new people to take these jobs. So the kind of mess-ups we've seen this past week, I think we're going to see over and over and over again."

Cohn's departure sends shock waves through the GOP, which had hoped Trump would scale back his tariffs on aluminum and steel and focus them on China rather than US allies. On Tuesday, about half a dozen Senate Republicans met with White House chief of staff John Kelly to discuss their concerns. And by Wednesday afternoon, during the daily press briefing at the White House, press secretary Sarah Sanders told reporters there could be potential carve-outs.

But Cohn's departure from the White House still left GOP senators worried that a crucial voice to push their position on something as critical as tariffs would be missing moving forward. There's also concern, multiple senior GOP aides told CNN, that some of Cohn's top aides at the National Economic Council -- considered by senior Republicans to be one of, if not the, most cohesive and effective policy teams in the White House, and central players themselves in the legislative push on taxes and financial regulation scale-back -- may soon leave as well.

"I don't think it's good news," Majority Whip John Cornyn of Texas, the second ranking Republican in the chamber, said Wednesday when asked what Cohn's departure meant for the future of trade discussions.

Sen. Susan Collins, a Republican from Maine, said she was sorry that "the President will no longer have the benefit of (Cohn's) advice."

Senators may now take an active role in attempting to influence who fills Cohn's shoes, trying to find someone who may share his views on things like trade and is able to offer substantive and clear guidance for lawmakers as they navigate the varying poles within the White House. Sen. Rob Portman, a Republican from Ohio and former US trade representative who worked closely with Cohn during the tax reform debate, said he had offered a few names to the White House, hoping to find someone who fit Cohn's mold.

"I've got some candidates I've been promoting," Portman said.

Senators said they were hoping to see the President pick a replacement that didn't just parrot Trump's populist views on issues like trade but instead offered other perspectives.

"It's my view that Gary Cohn worked hard to make sure the President heard all points of view on these issues, and I would hope that somebody else continues to play that role," one GOP senator told CNN.