Rep. Andy Barr, who announced support from more than 100 members of Congress, is aiming to project strength in a rancorous GOP race to succeed Sen. Mitch McConnell.
Aggressive tactics employed by Trump and his allies did not sit well with state lawmakers, who delivered a major political blow to national Republicans.
The president has been pressuring Indiana Republican lawmakers for months to pass new district lines that would boost the party in next year's midterms.
Nida Allam launched her campaign against Rep. Valerie Foushee with endorsements from multiple groups, signaling a more organized effort to take on incumbent Democrats.