The 79-year-old's absence raises doubts about the ability of GOP leaders to pass a key budget resolution -- a vote is planned later this week -- that is needed to advance tax reform, a top legislative priority for Republicans and President Donald Trump.
"Mrs. Cochran informed me late Saturday night that Senator Cochran has developed another urinary tract infection," said the statement from Cochran's chief of staff Brad White. "After a day of monitoring his condition, and on the advice of his physicians and other health care professionals, Senator Cochran has postponed his return to Washington. He will continue his recuperation at home in Mississippi."
White did not say if Cochran might be back in time for the vote, which, while not formally scheduled, is expected to take place late Thursday night or very early Friday morning, but the senator already has been out for several weeks.
Asked if the vote might be postponed to give Cochran time to recover, Senate Majority Leader Mitch McConnell spokesman Don Stewart said he did not have any scheduling announcements to make.
Republicans hold a narrow 52-48 majority in the Senate. To pass the budget resolution, they will need at least 50 GOP senators to vote "yes" and have Vice President Mike Pence break a tie. Right now, there are no Democrats who have said they will vote for the budget. The resolution is critical because it could lay the groundwork for tax reform to pass with 51 votes instead of the 60 often needed to pass major legislation.
This same technique was tried to pass a repeal and replacement bill for the Affordable Care Act but twice failed dramatically.
Currently, at least four Republicans senators are undecided: Bob Corker of Tennessee, Susan Collins of Maine, John McCain of Arizona, and Rand Paul of Kentucky. They cite various concerns, but Paul and Corker have said they are very concerned the tax overhaul could add to the budget deficit. Collins told ABC's "This Week" on Sunday that she is a "likely yes" on the budget.
GOP Senate leaders and the White House are working hard to convince the wavering senators to get on board. Paul played golf with Trump
this weekend and praised his tax proposal afterward but didn't say if he will vote for the resolution.
Before Cochran's illness, GOP leadership aides privately expressed confidence they would get the needed votes to pass the budget. But even if they do, it remains unclear if they can pass the tax reform bill itself, which is still being formulated through intense negotiations. Democrats have decried it as a series of tax break for wealthy Americans at the expense of the middle class.
Cochran's illness was cited by Trump late last month, shortly after health care efforts collapsed. The President wrongly suggested that Cochran was in the hospital, even though he wasn't
, and that health care would have passed otherwise.
Cochran tweeted a photo of himself last week
, in which he was sitting on a chair in street clothes chatting with his brother. That unexpected photo came the same day a Politico report raised questions about whether he would return to the Senate and continue chairing the powerful appropriations committee.
The statement from Cochran's office indicated the seven-term Mississippi lawmaker plans to resume his duties soon.
"The Senator has expressed his intention to return to the Senate when his health permits, and to fulfill his commitment and duties to the people of his state," it said.