On Sunday night, President Obama will address the nation from the Oval Office to discuss the threat posed by terrorism and his administration's response to it. The Oval Office speech is a tool that Obama has used with relative rarity, and is one that for decades has suggested that the topic at-hand was one of unusual seriousness. (You may remember that Obama's speech announcing military action against the Islamic State last September was given from a lectern at the White House.)

So why this topic, and why now? Probably in part because America was showing increased concern about the threat of terror attacks and skepticism about Obama's strategy to prevent them — even before San Bernardino.

A Washington Post/ABC News poll conducted shortly after the attacks in Paris in November found that concern by Americans about a major terror attack in the United States had increased substantially. That mirrored polling from Quinnipiac University and CBS News showing a big increase in that concern since last year — even before the Paris attacks.

That Post/ABC poll also found that a majority of Americans didn't have much confidence that the government could keep terrorists from striking again on U.S. soil. Fifty-five percent had only a fair amount of confidence that the government would be successful; 15 percent had no confidence at all.

At the same time, confidence in Obama's strategy for addressing the threat posed by the Islamic State has faded since last autumn. More than a third of Americans thought Obama had a clear plan to deal with ISIS militants last October. Last month, that fell under 25 percent in CBS News polling. Approval of his efforts in combating the Islamic State has also slipped during that period.

ABC/Post polling has seen a long-term slip in attitudes about how Obama's done in tackling terrorism. In late 2011, more than half of Americans thought he was doing well on that front. Last month, the figure was at 40 percent.

Support for the use of ground troops in the fight against the Islamic State has slipped upward. This is something Obama has adamantly opposed — even as he sends more military forces to do precisely that. In the Post/ABC poll from last month, 60 percent approved of increasing the number of troops employed in the fight (which is slightly different wording than the question posed in CBS and CNN/ORC polling over time).

Much of that support for using ground troops is from Republicans who, as always, are more critical of the Obama presidency than independents or Democrats.

Perhaps the most telling response from our most recent survey, offering insight into why Obama feels the need to address the situation at this moment, was when Americans were asked if the country was at war with radical Islam. The president's rejection of that term has been a point of repeated attack by his opponents, who often use it as a way of suggesting that Obama isn't serious about eradicating the Islamic State or taking it seriously.

In our survey, more than half of Americans — 59 percent — disagreed with that position, saying that the country is at war with radical Islam.

What Obama hopes to do on Sunday night is assure America that his approach to the Islamic State and the threat of terror attacks in the United States remains viable, despite much of the country disagreeing. It's a tough argument to make on an increasingly worrisome topic.

Hence the Oval Office.