Yes. It's called Rally around the Flag effect. From Wikipedia:
==================================
Rally 'round the flag effect
The
rally 'round the flag effect (or
syndrome) is a concept used in
political science and
international relations to explain increased short-run popular support of the
President of the United States during periods of
international crisis or
war. Because rally 'round The Flag effect can reduce criticism of governmental policies, it can be seen as a factor of
diversionary foreign policy.
. . .two schools of thought have emerged to explain the causes of the effect. The first, "The Patriotism School of Thought" holds that in times of crisis, the American public sees the President as the embodiment of national unity. The second, "The Opinion Leadership School" believes that the rally emerges from a lack of criticism from members of the opposition party, most often in the
United States Congress. If opposition party members appear to support the president, the media has no conflict to report, thus it appears to the public that all is well with the performance of the president. The two theories have both been criticized, but it is generally accepted that the Patriotism School of thought is better to explain causes of rallies, while the Opinion Leadership School of thought is better to explain duration of rallies.It is also believed that the lower the presidential approval rating before the crisis, the larger the increase will be in terms of percentage points because it leaves the president more room for improvement. For example, Franklin Roosevelt only had a 12% increase in approval from 72% to 84% following the
Attack on Pearl Harbor, whereas George W. Bush had a 39% increase from 51% to 90% following the
September 11 attacks.
================
Some examples:
GWB saw significant jumps in his approval when we invaded Iraq and again later when we captured Hussein.
JFK saw a significant increase after the Cuban Missile Crisis.
GHWB - big jump when Desert Storm started
Trump desperately wants a high approval rating. So he uses the tools at his disposal to achieve that.