ISIS threats combined with the Paris attacks have brought thoughts of a threat here at home to the minds of many. But just how possible is a potential terrorist attack here in the United States?
"It is a threat, it is possible. The likelihood? It's difficult to tell at this point," said Dean Alexander, Homeland Security Research Program director at Western Illinois University in Macomb.
Alexander is also co-author of a book focused on combating ISIS, a group he describes as violent jihadists.
"The threats have already existed. It's likely that some individuals may be further radicalized by this activity and may want to emulate this activity," Alexander said.
Multiple states, including Illinois, announced they will stop taking in Syrian refugees in light of what happened in Paris. But alexander says previous attempts show the group has already made an impact inside our borders.
"You had he attack at an art exhibition in Garland, Texas by two individuals that were inspired by ISIS including some that were apparently in contact with some ISIS operatives," said Alexander.
Like the targets in Paris, Alexander says if the group does attack the U.S. it wouldn't have to be at a military institution.
"They're looking for high levels of civilian casualties. How much can you buttress security at a business or other institution that by their nature allows for fast rapidity of service and ease of entry and exit," said Alexander.
It's a threat that requires many changes be made.
"To combat that, you need increased awareness by the public, by consumers. You also need more aggressive action in a military posture and at the same time a higher level of activity in the law enforcement intelligence community. And I think you'll be seeing that in the coming days and weeks," explained Alexander.
The state department says it won't change its plan to accept ten thousand syrian refugees in the next year. President Barack Obama said Monday adding a religious test for refugees would be shameful.