"Mitch McConnellMitch McConnellFive takeaways from the Indiana primary Reid: Judiciary a 'rubber stamp' for Trump-McConnell Iran and heavy water: Five things to know MORE's quiet, principled leadership is key to everything we accomplish on Capitol Hill," Rubio said during the event, according to CNN.
"The way he fought ObamaCare, tooth and nail, and forced the Democrats to use extraordinary measures to pass it was a critical catalyst in electing my entire class of Senate conservatives in 2010. Without Mitch, I don't know that we'd have Senator Rubio, Senator Johnson, Senator Paul or Senator Lee."
Sens. Ron JohnsonRon JohnsonKoch network super-PAC launches ad buys in Wisconsin, Nevada Senators urge White House to speed cyber policy updates Mellman: Fissures and factions MORE (R-Okla.), Rand PaulRand PaulGOP operative Ed Rollins joins pro-Trump super-PAC Overnight Energy: Clinton makes her pitch to coal country Rand Paul calls on Clinton to apologize for coal job losses MORE (R-Ky.) and Mike LeeMike LeeReid: Cruz, Lee on Supreme Court should 'scare you' Cruz: Boehner unleashed his ‘inner Trump’ Senate pressured to take up email privacy bill after overwhelming House vote MORE (R-Utah) all have Tea Party support, and affiliating himself with all three will likely help McConnell appeal to those skeptical voters on the right.
McConnell is likely to face a strong challenge from Democrats as well, who believe he is one of the nation's most vulnerable incumbents in 2014. Two Democratic contenders, actress Ashley Judd and Kentucky Secretary of State Alison Lundergan Grimes, have emerged as possible challengers.