Are U.S. citizens still able to travel?

There are very few international destinations that accept travelers from the US due to the high rates of coronavirus infection in the US. Other than diplomats and essential travel there aren't many options.

For now, just travel in the US. There's plenty to see and do.

Besides, if you're like me, you don't get to travel abroad 

every year anyway.

Most other countries don't want people entering from the US, given the transmission / virus levels there.

Yes they can travel.  There are no restrictions against them entering Tunisia or the Dominican Republic.

YES US Citizens can and do travel to other countries.

MOST are aware there is a world wide Corona Virus pandemic and plan accordingly for the destination place specifics.

TOURISM is not recommended at this time. MOST cannot afford the two weeks time at the start and end of journey for self isolation.

COVID-19 TravelAugust 6, 2020The U.S> Department of State advises all U.S. citizens to read the>>> country-specific <<<Travel Advisories and U.S. Embassy COVID pages for updates on the impact of COVID-19 worldwide. The COVID-19 pandemic continues to affect countries differently. Challenges to any international travel at this time may include mandatory quarantines, travel restrictions, and closed borders. Foreign governments may implement restrictions with little notice, even in destinations that were previously low risk. If you choose to travel internationally, your trip may be severely disrupted, and it may be difficult to arrange travel back to the United States.

Suggest you plan your tourism for NEXT year the scenery will be there waiting for you.