WASHINGTON — A Virginia woman makes a point to get out and go jogging. A Texas mom stays in and snuggles her toddler a little closer. A nurse from Massachusetts looks over her shoulder more often while touring D.C.

Strains of defiance, tenderness and wariness are interwoven as Americans are forced to do some post-9-11 rebalancing in the aftermath of the Boston bombings, figuring out how to move forward with life while remaining vigilant against the threat of terrorism.

The discovery of tainted letters sent to the Capitol and the White House only added a new source of jitters to the week’s events, evoking eerie parallels to the anthrax attacks that followed the life-altering events of Sept. 11, 2001.

For Simone Rinaldi, playing tourist in Washington this week with her family, the twin bombings at the marathon quickly revived thoughts of the collapse of the Twin Towers in New York as she wondered anew if there would be other attacks and whether loved ones in Boston were safe.

“I’ve definitely been more cautious as we walk around,” said Rinaldi, a nurse practitioner from Cape Cod, Mass.

Cautious, yes. But not cowed.

“The world is a really scary place, yet we have a life to live,” she said from a park across from the White House. “The challenge is to take precautions, but again to not let our lives get small and live in fear.”

Similar sentiment echoed around the country, from a Starbucks table in Los Angeles to a smokers’ bench in Billings, Mont., as people grappled with the balancing act involved in putting the week’s events in perspective.

“Caution is always important, but so is life,” said MacKenzie Edwins, a receptionist eating lunch at the Starbucks in LA.

Jennifer Miller, a hospitality industry manager smoking a cigarette on that bench in Montana, said the marathon bombing made her think, “It’s at home in America. It happened here.” But also, “I refuse to live in fear of going anywhere or doing anything.”

Such perspective is precisely what terrorists try to destroy, by provoking reactions far out of proportion to actual danger.

Horrific as the bombing was — three people died in Boston, with more than 170 injured — five people die in car, truck or motorcycle accidents every hour in the U.S. Terrorism pushes our fear buttons, said security expert Bruce Schneier, and we have an outsized response.

“Psychologically, we are primed to overreact,” he said.

And that can cause people to surrender civil liberties without full deliberation in pursuit of safety and stronger law enforcement, as happened after 9-11, Schneier said. “The fear is that this is an excuse to put us into a police state.”

Around the country, people wondered whether the bombing would — and should — affect security restrictions.

Security may increase for a time, but “the sad thing is it always goes back to normal,” said Lynn Chamberlain, a training coordinator at Johns Hopkins Medicine in Baltimore.

“Now we’re going to have to raise up not only our national security but our local security,” said Zeke Reardon, a Denver electrician.

Terrorism peaked as a public concern just one month after the 9/11 attacks. In October 2001, Gallup found that 46 percent of Americans called terrorism the most important problem facing the country, compared to less than 1 percent in the days before the attack.

It has not reached that level of importance since, and in surveys this year, it once again stood at less than 1 percent.

But while it may not be Issue No. 1, security nonetheless remains a priority for most Americans. In a January 2013 poll by the Pew Research Center, 71 percent said defending against terrorism should be a top priority for the president and Congress, down just 5 points from four years earlier.

Runners in particular seemed to push back against the notion that the marathon bombing could intimidate Americans.

Spontaneous running events popped up around the country — one is planned for Charleston on Sunday — and social media was filled with posts from those pulling on their sneakers to send a message.

“I am going running today as a small sign of support for Boston and to show those responsible for the tragic events that we are stronger than they are,” Ironman CEO Andrew Messick said in an email to athletes.