Fiala's other coalition partner

Is there any real doubt about who would win if PM Petr Fiala were forced to choose between Army Chief of Staff Karel Řehka and Defense Min. Jana Černochová of ODS? Normally when a minister is replaced, it's up to the nominating party's chairperson to make the decision. That's what the coalition agreement calls for, and Fiala respected it when KDU-ČSL decided last year to replace Anna Hubáčková as environment minister, even though there were rumors that he and Justice Min. Pavel Blažek weren't thrilled with KDU's nominee, Petr Hladík. If Fiala wanted to remove one of ODS's own ministers, he, like any other party head, would have to answer to his party's interest groups. When it's the defense minister, there's the added "coalition partner" of Nato and the U.S. defense establishment. Řehka is a proven element for them. By comparison, Černochová is a lightweight, but her position is probably secure until the Defense Cooperation Agreement is ratified and signed by Pres. Petr Pavel.