Russian Federation President Vladimir Putin has proven himself to be—in the words of Charles Murphy—a habitual line-stepper.

Yesterday, March 18th, a raid-style attack was conducted at Simferopol, in Ukraine, that killed at least one Ukrainian soldier. This attack was conducted by Russian forces without uniforms or insignia, and without avowal by the Russian government, in sovereign Ukrainian territory which Russia alleges to be theirs. Putin’s demonstrated disregard for treaties, norms and international law creates insecurity for our allies, and our businesses, that depend on Russia to abide by these parameters.

Ambassador McFaul resigned last month to return to Stanford University's Hoover Institution, leaving us without a dedicated official envoy to Moscow. We need an Ambassador to advocate for regional stability and economic confidence. We need an Ambassador right now to be a stone in the Putin administration's shoe, always present and felt with every step. This is not something we should expect of either the Secretary of State or the Deputy Chief of Mission in Moscow, who each have other responsibilities.

Finally, we need an Ambassador with a detailed knowledge of existing US capability across every agency and department; a proven ability to deliver finely calibrated messages in volatile situations; and a keen awareness of the ability and willingness of our allies to stand beside us under any given set of circumstances.

Ambassador McFaul and General Mattis have been colleagues at the Hoover Institution for the past six weeks, where they have undoubtedly been talking through this Ukraine crisis as it has unfolded from unrest, to the shooting of protesters, to the ouster of President Yanukovych, and finally to an undeclared Russian invasion of Crimea.

For these reasons, we ask President Obama to nominate General Mattis to be the United States Ambassador to the Russian Federation.