In less than a week Trump can start laying off government workers who are not getting paid

Thomas Lifson:

Has President Trump suckered Democrats and the Deep State into a trap that will enable a radical downsizing of the federal bureaucracy? In only five more days of the already "longest government shutdown in history" (25 days and counting, as of today), a heretofore obscure threshold will be reached, enabling permanent layoffs of bureaucrats furloughed 30 days or more.

Don't believe me that federal bureaucrats can be laid off? Well, in bureaucratese, a layoff is called a RIF – a Reduction in Force – and of course, it comes with a slew of civil service protections. But, if the guidelines are followed, bureaucrats can be laid off – as in no more job. It is all explained by Michael Roberts here (updated after the beginning of the partial shutdown):

A reduction in force is a thoughtful and systematic elimination of positions. For all practical purposes, a government RIF is the same thing as a layoff. ...

Organizations must stick to predetermined criteria when sorting out what happens to each employee. They must communicate with employees how and why decisions are made. ...

In deciding who stays and who goes, federal agencies must take four factors into account:

1. Tenure

2. Veteran status

3. Total federal civilian and military service

4. Performance

Agencies cannot use RIF procedures to fire bad employees.

A lot of procedures must be followed, and merit ("performance") is the last consideration, but based on the criteria above, employees already furloughed can be laid off ("RIFed") once they have been furloughed for 30 days or 22 work days:

When agencies furlough employees for more than 30 calendar days or 22 discontinuous work days, they must use RIF procedures.

An employee can be terminated or moved into an available position[.]

This seems to be what was referenced in this remarkable essay written by an "unidentified senior Trump official" published in the Daily Caller, which vouches for the authenticity of the author and explains that it is protecting him from adverse career consequences should the name become known. I strongly recommend reading the whole thing.
...

There is much more.

One of the problems the Democrats face in this situation is that many of the people have already been deemed "nonessential."   I think there could be some overlap between employees with poor performance records and "bad employees."

Trump would be unlikely to lay off people working for ICE or the Border Patrol  He would be more likely to do so from employees in other agencies the Democrats have been trying to get up and running again.