The one-year mark of new U.S. military operations in Iraq is Saturday.
And lawmakers still haven't authorized the fight.
"The theater of battle is growing," Sen. Tim Kaine, D-Va., said. "We've seen other groups swearing allegiance to [the Islamic State group]. The Turks are getting involved. We've seen reports that the U.S. can take military action against Syria if they try to mess with our anti-ISIL fighters.
"This thing is creeping and growing. And Congress has not said anything about it."
ISIL is an alternative acronym for the Islamic State militant group.
Kaine, who for the past year has been the leading voice for a new military authorization of force in the region, expressed frustration and dismay to reporters Thursday that those efforts so far have been unsuccessful.
White House officials last year started airstrikes and military training work in Iraq under the legal logic that previous force authorizations covered the threat posed by Islamic State fighters. But administration officials relented somewhat earlier this year, sending a new authorization draft to Congress for consideration.
Despite repeated promises from congressional leaders that the issue was a top priority for them, those drafts have been pushed aside amid extended debate over the new nuclear monitoring arrangement with Iran.
Kaine said he is hopeful that Congress will still take up the work soon, but acknowledged it's likely to be late September or October before talks even resume. The Iran deal deserves oversight, he said, "but I think it's ironic that (Congress) wants to challenge diplomacy but is OK with war."
Republican leaders already have scheduled votes on the Iran deal next month, in what is expected to be a foreign policy showdown between the White House and its critics.
Meanwhile, Kaine's newest proposal for a new Iraq authorization — drafted with Arizona Republican Sen. Jeff Flake — remains stalled.
About 3,500 U.S. troops are stationed in Iraq, and seven have lost their lives in connection to the new military operations there.
Kaine said administration officials have reached out to him to ask for a continued push on the issue. But when asked if he sees a quick path forward, he said: "I don't have any trick up my sleeve to make this move ahead."
"It's not hard to imagine a U.S. service member being shot down over there ... and ISIL may try to commit some public atrocity with a U.S. service member," he said. "If it does happen, I know this body would act within a day and a half on something.
"But we shouldn't wait for that."