In a news conference Wednesday that was largely about international relations and trade, President Obama also addressed the limits of his own authority at home.
"I never have a green light," Obama said. "I'm bound by the Constitution; I'm bound by the separation of powers."
The question of whether Obama has overstepped the bounds of his executive authority has been much in the news of late, with the House voting last week to authorize a lawsuit challenging the president on this issue.
Obama's own approval ratings hit a new low in an NBC News/Wall Street Journal poll released Wednesday.
Obama said he would much prefer to work with Congress on issues such as job creation and infrastructure spending, noting that laws make for solutions that are more ambitious and longer-lasting.
But he said he would continue to do what he can to help middle-class Americans, particularly when Congress cannot act.
"What the American people expect is that despite the differences between the parties, there should at least be the capacity to move forward on things that we agree on, and that's not what we're seeing right now," Obama said.
He said his administration is revisiting statutes that govern multinational corporations with extensive operations in the U.S. that move their headquarters abroad to reduce their tax bill.
Obama said that for companies that are clearly American with extensive domestic operations, it's not right or fair that they skip out on paying taxes through a loophole.
The president said that the issue concerns only a small number of companies — Walgreens on Wednesday announced it would not move its headquarters overseas — but that "we don't want to see this thing grow."
Obama spoke at the State Department, at the end of a three-day summit with African leaders. He said he had spoken with them about a wide range of issues, including press freedom, security issues and the need to address corruption issues.
The U.S. will continue support efforts to build trade among African nations and with partners beyond the continent, he said.
"This summit reflects the reality that even as Africa continues to face great challenges, we're also seeing the emergence of a more prosperous Africa," Obama said. "This summit has helped to mobilize some $37 billion for Africa's progress."
In response to a question about whether it was fair or ethical for two Americans to have received treatment with an experimental Ebola drug while hundreds of Africans have died from the disease in recent weeks, the president said, "We've got to let the science guide us. I don't think all the information is in as to whether this drug is helpful."
He noted that Ebola is not an airborne disease and can be contained if proper protocols are followed.
"The countries that are involved would be the first to admit, what's happened here is their public health systems have been overwhelmed," Obama said.
The president also addressed a pair of the major foreign policy crises of the moment. With regard to Russia gathering additional troops on its border with Ukraine, Obama repeated his assertion that Russian President Vladimir Putin has a "choice" as to whether he will respect Ukrainian sovereignty, or watch his own country suffer as it becomes more isolated economically.
"What you're seeing is that the [Russian] economy has ground to a halt," Obama said, referring to sanctions imposed recently by the U.S. and the European Union. "You're not seeing a lot of investors coming in new to start businesses inside of Russia."
He dismissed the idea of providing arms to Ukraine, noting that its army is already better equipped than the separatists it's been fighting, but is a much smaller force than the Russian military, should that country invade.
With regard to Israel and the situation in Gaza, Obama applauded the current cease-fire and said the administration is supporting efforts to make it sustainable.
He repeated his support for Israel to defend itself and said it couldn't tolerate rockets being fired at its population.
"I've also expressed my distress at what's happened to innocent civilians, including women and children, during the course of this process," Obama said.
In addition to expressing concern about Israeli security, Obama noted that the people of Gaza must have a chance to rebuild and have some sense of hope going forward.
"I have no sympathy for Hamas," Obama said. "I have great sympathy for ordinary people struggling within Gaza."